Crossfire Error

I have a problem starting my crossfire then and the following:
1 - Start game
2 - Update
3-end to update my AVG antivirus detects a trojan horse injector X
4 - after it happens I can not play
5 - already did download the west coast mirror 4 does not work and says that the files are old
I would like to help me please because I love playing crossfire .. thanks