The "tweak repair" is nothing really serious. The program Tweak UI is from the Microsoft website (although they don't officially support it). It won't do any harm to run it and do the repair. Worst case scenario, you'll have wasted 10 - 20 minutes downloading, installing, and running the program. Here's a link to download it from Microsoft's website:
http://www.microsoft.com/ntworkstati.../NTTweakUI.asp