legacyshader-error

Hey guys,
ive a problem with my crossfire: when i join a game i become an error: can not open shader file: (\rez\shader\legacyshader.fxo)

-i used ccleaner
-i disabled my Antivirus programm and my firewall. Then i download, install und patch it again (after uninstall)
-i reinstall my g-drivers (up to date)
-i restart my computer a few times
but every time i try to play it shows me the same error .....
and No I NEVER used Hacks or other mods

Nvidia Geforce GTX 660Ti 2GB DDR5
AMD FX 8350 Eight-Core 4,0Ghz
Adata SSD S510 120GB
8 GB DDR3 (1600Mhz)

so how i fix that ******* error?