Crossfire 1.81 - Install Error

I made a clean install ( I have done this a lot of times )
And I get the same error while trying to activate the mod ( in FLMM 1.31 )
And it goes like this :

Error: problem activating 'Crossfire Mod 1.81 Client Edition'
Error: SHCopyFile failed ('C:\Program Files\Freelancer Mod Manager\mods\Crossfire1.81\EXE\Freelancer.exe' to 'C:\Program Files\Microsoft Games\Freelancer\EXE\Freelancer.exe')

PS: I downloaded the mod at least three times by now, and still no luck.

HELP !!!
Please.

EDIT: [SIZE=3]Never mind, I solved the problem. It was my Antivirus (AVG). Deactivating did not help! I had to uninstall it![/SIZE]