Help on guage XML NameSpace

System.Windows.Markup.XamlParseException: The tag 'CircularGauge' does not exist in XML namespace 'http://schemas.actiprosoftware.com/winfx/xaml/gauge'. Line '50' Position '22'.

<UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             xmlns:gauge="http://schemas.actiprosoftware.com/winfx/xaml/gauge"
             xmlns:shared="http://schemas.actiprosoftware.com/winfx/xaml/shared"
             xmlns:system="clr-namespace:System;assembly=mscorlib"
             xmlns:themes="http://schemas.actiprosoftware.com/winfx/xaml/themes"             Background="#F8F8F8"
             mc:Ignorable="d" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" Height="400" Width="251">

    <UserControl.Resources>

        <!-- Data Providers -->
        <ObjectDataProvider x:Key="backgroundTypeObjectDataProvider" MethodName="GetValues" ObjectType="{x:Type system:Enum}">
            <ObjectDataProvider.MethodParameters>
            </ObjectDataProvider.MethodParameters>
        </ObjectDataProvider>
        <ObjectDataProvider x:Key="glassTypeObjectDataProvider" MethodName="GetValues" ObjectType="{x:Type system:Enum}">
            <ObjectDataProvider.MethodParameters>
            </ObjectDataProvider.MethodParameters>
        </ObjectDataProvider>
        <ObjectDataProvider x:Key="rimTypeObjectDataProvider" MethodName="GetValues" ObjectType="{x:Type system:Enum}">
            <ObjectDataProvider.MethodParameters>
            </ObjectDataProvider.MethodParameters>
        </ObjectDataProvider>

        <!-- Converters -->


    </UserControl.Resources>

    <Grid Margin="10" Width="570">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="10" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="10" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <ScrollViewer Grid.Row="4" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" Margin="0,0,338,43">
            <StackPanel Orientation="Horizontal" Height="306" Width="221">

                <StackPanel>

                    <!-- CirularGauge -->
                   
                    <gauge:CircularGauge x:Name="gauge" Width="220" Height="220" Radius="110" HorizontalAlignment="Left"
                            Background="#FF5D1E1E" RimBrush="#FF363065" FrameType="CircularThickRimEclipse">
                        <gauge:CircularGauge.BackgroundGeometry>
                            <Geometry>M 1,0 L 2,0 L 3,1 L 3,2 L 2,3 L 1,3 L 0,2 L 0,1 Z</Geometry>
                        </gauge:CircularGauge.BackgroundGeometry>
                        <gauge:CircularGauge.RimGeometry>
                            <Geometry>M 1,0 L 2,0 L 3,1 L 3,2 L 2,3 L 1,3 L 0,2 L 0,1 Z</Geometry>
                        </gauge:CircularGauge.RimGeometry>

                        <gauge:CircularGauge.LayoutTransform>
                            <ScaleTransform ScaleX="{Binding ElementName=scaleSlider, Path=Value}"
                                    ScaleY="{Binding ElementName=scaleSlider, Path=Value}" />
                        </gauge:CircularGauge.LayoutTransform>

                        <gauge:CircularGauge.Items>
                            <TextBlock x:Name="textBlock" gauge:CircularGauge.Y="-30" Text="sacmi" FontFamily="Script MT"
                                    Foreground="WhiteSmoke" FontSize="19" />
                        </gauge:CircularGauge.Items>

                        <gauge:CircularGauge.Scales>
                            <gauge:CircularScale Radius="74" StartAngle="170" SweepAngle="200"
                                    Background="{shared:LinearGradientBrush DarkGray, Gray, GradientType=TopToBottom}">
                                <gauge:CircularScale.TickSets>
                                    <gauge:CircularTickSet MajorInterval="10" MinorInterval="2" gauge:CircularScale.SweepAngle="360" Maximum="360" gauge:CircularGaugeBase.Radius="75px" gauge:CircularScale.StartAngle="270" IsManipulationEnabled="True" LogarithmicBase="10" gauge:ScaleBase.BarExtent="4px" IsLogarithmic="False" AllowDrop="False">
                                        <gauge:CircularTickSet.ContextMenu>
                                            <ContextMenu />
                                        </gauge:CircularTickSet.ContextMenu>
                                        <gauge:CircularTickSet.Ticks>
                                            <gauge:CircularTickMarkMinor TickMarkAscent="3" ScalePlacement="Outside" ScaleOffset="1"
                                                    Background="{shared:LinearGradientBrush Black, DarkGray, GradientType=TopToBottom}" />
                                            <gauge:CircularTickMarkMajor ScalePlacement="Outside" ScaleOffset="1"
                                                    Background="{shared:LinearGradientBrush Black, DarkGray, GradientType=TopToBottom}" />
                                            <gauge:CircularTickLabelMajor FontFamily="Tahoma" TextOrientation="Rotated" ScalePlacement="Inside" Focusable="True" Foreground="#FFFFDEDE" MinorInterval="0" MajorInterval="1" StartValue="NaN" EndValue="NaN" gauge:TickSetBase.MajorInterval="1" gauge:TickSetBase.Maximum="15" gauge:TickSetBase.MinorInterval="1" gauge:TickSetBase.Minimum="0" gauge:TickSetBase.MinorIntervalType="Auto" gauge:TickSetBase.IsReversed="False" gauge:TickSetBase.IsLogarithmic="False" IsManipulationEnabled="True" HasDropShadow="True" OpacityMask="{x:Null}" DataContext="{Binding}" MinimumTickVisibility="Always" Angle="0" gauge:CircularGaugeBase.Radius="102px" FontWeight="Bold" gauge:GaugeBase.X="0px" MaximumTickVisibility="Always" gauge:ScaleBase.BarExtent="4px" MinorIntervalType="Auto" gauge:TickSetBase.MajorIntervalType="Linear" IntervalOrigin="Zero" MajorIntervalType="Auto" OverridesDefaultStyle="False"></gauge:CircularTickLabelMajor>
                                        </gauge:CircularTickSet.Ticks>
                                        <gauge:CircularTickSet.Pointers>
                                            <gauge:CircularPointerNeedle
                                                    Background="{shared:LinearGradientBrush #FFEF153F, #FFEB7A8A, GradientType=LeftToRight, AdditionalStopCount=1}"
                                                    NeedleType="PivotSwordSharp"  PointerExtent="78" PointerAscent="10" />
                                        </gauge:CircularTickSet.Pointers>
                                    </gauge:CircularTickSet>
                                </gauge:CircularScale.TickSets>
                            </gauge:CircularScale>
                        </gauge:CircularGauge.Scales>

                    </gauge:CircularGauge>

                    <!-- Standard Options -->
                    <Grid Margin="0,10,0,0">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="3" />
                            <RowDefinition Height="Auto" />
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto" />
                            <ColumnDefinition Width="Auto" MinWidth="100" />
                            <ColumnDefinition Width="Auto" />
                        </Grid.ColumnDefinitions>

                        <TextBlock Margin="0,0,7,0" Text="Value" HorizontalAlignment="Right" VerticalAlignment="Center" />
                        <Slider x:Name="valueSlider" Grid.Column="1" Minimum="0" Maximum="100" LargeChange="10" SmallChange="1"    
                                Value="{Binding ElementName=gauge, Path=Scales[0].TickSets[0].Pointers[0].Value, Mode=TwoWay}"
                                IsMoveToPointEnabled="True" IsSnapToTickEnabled="True" TickFrequency="1" HorizontalAlignment="Left" Width="100" />
                        <TextBlock Grid.Column="2" Margin="3,0,0,0" Text="{Binding ElementName=valueSlider, Path=Value}"
                                HorizontalAlignment="Left" VerticalAlignment="Center" />

                        <TextBlock Grid.Row="2" Margin="0,0,7,0" Text="Scale" HorizontalAlignment="Right" VerticalAlignment="Center" />
                        <Slider x:Name="scaleSlider" Grid.Row="2" Grid.Column="1" Minimum="1" Maximum="3" LargeChange="0.5"
                                SmallChange="0.1" Value="1" IsSnapToTickEnabled="True" TickFrequency="0.1" />
                        <TextBlock Grid.Row="2" Grid.Column="2" Margin="3,0,0,0"
                                Text="{Binding ElementName=scaleSlider, Path=Value, Converter={StaticResource PercentageConverter}, ConverterParameter=%}"
                                HorizontalAlignment="Left" VerticalAlignment="Center" />

                    </Grid>
                </StackPanel>

                <StackPanel Margin="25,0,0,0" Grid.IsSharedSizeScope="True">

                    <!-- Frame Options -->
                    <!-- TextBlock Options -->
                </StackPanel>
            </StackPanel>
        </ScrollViewer>
    </Grid>
</UserControl>