When I try to import the System.Linq namespace to Boo compiler, I get this error:

Boo.Lang.Compiler.CompilerError:

Namespace 'System.Linq' not found, maybe you forgot to add an assembly reference?

I use "Rhino.DSL.dll" and my DSL engine code is here:

public class MyDslEngine : DslEngine
{
    protected override void CustomizeCompiler(BooCompiler compiler, CompilerPipeline pipeline, string[] urls)
    {
        pipeline.Insert(1, new AnonymousBaseClassCompilerStep(typeof(DslBase), "Prepare",
            "System.Linq",
            "Azarakhsh.Framework.Repository" //it's my repository framework
            ));
        pipeline.Insert(2, new UseSymbolsStep());
        pipeline.Insert(3, new RunScriptCompilerStep());
    }
}