Scala plugin cannot see the scala compiler

I installed scalla on IDEA 10.5 but something is not write. When I open module setting and scala facet,

The compiler library is marked with red letters none.

I spend several hours on this and there is no settings how to configure the scala compiler for the plugin.

I installed scala 2.8 and configured my environment so it is in the path and also SCALA_HOME is set too.

I am using Linux 64bit ( Fedora).