mmm Guys, I am on Windows 7 x64 and I dont have nor did have problems, and I tried out a LOT of themes, inclusive OLD ones.
I had MC 13 on this PC, briefly a MC14 trial, and now the 15 beta and NO problems.
Before each install I exported database (and settings from 14 on), uninstalled MC totally, did a registry clean up, reinstalled new version, restored licence, database and settings.
Skins always worked OK.
If you guys need me to do some testing I am available for that.