HI DM,
what service packs and updates do you have installed?
Do you have the MS Hotfix Q329170 installed? This might be the culprit as it was for me.
here is thread of my similar problem so not sure if same as yours but sounds like it to me.
http://www.techimo.com/forum/tid4958...pn2/index.html
the fix for it came to me on the second page, which is the link upabove.