Problem - Design Mode adding mysterious tags automatically

I am having a really odd problem. I use spiderwriter on two computers and have been for over a year with no complaints at all. Recently on one PC only, when i view a document in design view, then go back to document view, it is automatically adding tags and code for no apparent reason, it knocks the entire page layout out and i have no idea why its happening. I open the same document on the other PC and as always its fine. I have ruled out the possibility of the code being faulty, re-installed a fresh copy of spiderwriter and thus have ruled out it being a spiderwriter "problem", i have ruled out the files being corrupted by transfer from one pc to another as documents created on the "bad" PC also have the same probelm....

Examples of the code added automatically that ruin the page is, each time a document is saved:

</table>
</center>
</body
</body
</body
</body
</body
</body>
</html>

The above code is what happens when a document has been saved 5 times, a </body is added each time i save. Along with this letters are being deleted from page text and also code text, Verdana will become erdana, Welcome will become elcome etc.

Also tags such as DESIGNTIMURL= and DESIGNTIMEP="11032" are also being added upon save if the page is in Design view at the time, knocking the page layout out even further.

I have searched and searched and cannot see any reason for this and have only just discovered how to re-create the problem, saving in design mode....

Does anyone have any ideas why this maybe happening or suggestions of anything i could try? Could it be a setting i have on spiderwriter that i have set given its a re-creatable error?

Thanks in advance

"Frustrated Web Developer" Sam <IMG SRC="confused.gif" border="0">