No offense taken, just trying to understand as I do not see this problem in my own testing. No, I did not connect your post with the recent blog post as it wasn't mentioned.
If I understand now, are you saying this problem happens when mojoPortal is served from windows or from Mono?
In my testing with IE7 using both XP and Win 2003 server techmania skin looks just fine when served from windows. I have not tested in IE using the Mono installation.
Are you sure its IE7 and not IE6 you are using?