Avast Error In Linux: Unable to Initialize Avast Engine

Hi,
I have installed avast on Fedora, Genotoo, Sabayon, Ubuntu 11 and 12.04, But whenever I try to use it, I’m getting an error message : “Invalid Argument” or root@localhost avast, or root@localhoste avast is unable to initialize avast engine. There is no such directory. Can this error be fixed?
Please give me simple instructions to fix it.
