One user has a DockManager load problem

I have an application which installs and runs correctly for all users but one. For that user, the following crash happens on startup:

System.FormatException: Input string was not in a correct format.
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
at System.Convert.ToInt32(String value)
at e.a(DockManager A_0, XmlTextReader A_1, ToolWindowState A_2, Int32& A_3)
at e.b(DockManager A_0, XmlTextReader A_1)
at e.c(DockManager A_0, XmlTextReader A_1)
at e.a(DockManager A_0, XmlTextReader A_1)
at e.h(DockManager A_0, XmlTextReader A_1)
at ActiproSoftware.UIStudio.Dock.DockManager.LoadToolWindowLayoutFromFile(String path)

The layout file being loaded is verified as the same for this user as for all others, as is the version/configuration of our application. This same error was seen when we asked the user to install a completely different application that uses the same Base GUI.

The above stack trace, however, doesn't give me much help in trying to fix the issue for this user -- I don't know what's failing. Can you give me any hints on what to look for?