Miktex in win7, why does it happen?

[rode]

Hi,
I just encountered a sticky problem. I installed the the miktex in C:\Miktex and, when i compiled my *.tex file an error happened,
the required file
\tex\latex\revtex4\revtex4.cls is missing.

Well, it is really kidding i just placed the package revtex4 right there and the file that required is in it too. What is wrong with it? anything to do with the win7 system?

 

[Gornot]

Probably... I experienced some weird save/edit/delete issues when putting or executing files from C:\
So your best bet is to move the folder somewhere else