Tons of compiler Errors.. Please help ;_;

Internal compiler error. See the console log for more information. output was: Unhandled Exception: System.TypeLoadException: Could not load type 'System.Func`1' from assembly 'mscorlib, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'.

at (wrapper managed-to-native) System.Reflection.MonoMethodInfo:get_method_info (intptr,System.Reflection.MonoMethodInfo&)

at System.Reflection.MonoMethodInfo.GetMethodInfo (IntPtr handle) [0x00000] in :0

at System.Reflection.MonoMethodInfo.GetAttributes (IntPtr handle) [0x00000] in :0

at System.Reflection.MonoMethod.get_Attributes () [0x00000] in :0

at System.Reflection.MethodBase.get_IsVirtual () [0x00000] in :0

at Mono.CSharp.MemberCache.AddMethods (BindingFlags bf, System.Type type) [0x00000] in :0

at Mono.CSharp.MemberCache.AddMethods (System.Type type) [0x00000] in :0

at Mono.CSharp.MemberCache..ctor (IMemberContainer container) [0x00000] in :0

at Mono.CSharp.TypeHandle..ctor (System.Type type) [0x00000] in :0

at Mono.CSharp.TypeHandle.GetTypeHandle (System.Type t) [0x00000] in :0

at Mono.CSharp.TypeHandle.GetMemberCache (System.Type t) [0x00000] in :0

at Mono.CSharp.TypeManager.MemberLookup_FindMembers (System.Type t, MemberTypes mt, BindingFlags bf, System.String name, System.Boolean& used_cache) [0x00000] in :0

at Mono.CSharp.TypeManager.RealMemberLookup (System.Type invocation_type, System.Type qualifier_type, System.Type queried_type, MemberTypes mt, BindingFlags original_bf, System.String name, IList almost_match) [0x00000] in :0

at Mono.CSharp.TypeManager.MemberLookup (System.Type invocation_type, System.Type qualifier_type, System.Type queried_type, MemberTypes mt, BindingFlags original_bf, System.String name, IList almost_match) [0x00000] in :0

at Mono.CSharp.Expression.MemberLookup (Mono.CSharp.CompilerContext ctx, System.Type container_type, System.Type qualifier_type, System.Type queried_type, System.String name, MemberTypes mt, BindingFlags bf, Location loc) [0x00000] in :0

at Mono.CSharp.Expression.MemberLookup (Mono.CSharp.CompilerContext ctx, System.Type container_type, System.Type qualifier_type, System.Type queried_type, System.String name, Location loc) [0x00000] in :0

at Mono.CSharp.MemberAccess.DoResolve (Mono.CSharp.ResolveContext ec, Mono.CSharp.Expression right_side) [0x00000] in :0

at Mono.CSharp.MemberAccess.DoResolve (Mono.CSharp.ResolveContext ec) [0x00000] in :0

at Mono.CSharp.Expression.Resolve (Mono.CSharp.ResolveContext ec, ResolveFlags flags) [0x00000] in :0

at Mono.CSharp.Invocation.DoResolve (Mono.CSharp.ResolveContext ec) [0x00000] in :0

at Mono.CSharp.Expression.Resolve (Mono.CSharp.ResolveContext ec, ResolveFlags flags) [0x00000] in :0

at Mono.CSharp.Expression.Resolve (Mono.CSharp.ResolveContext ec) [0x00000] in :0

at Mono.CSharp.Return.DoResolve (Mono.CSharp.BlockContext ec) [0x00000] in :0

at Mono.CSharp.ExitStatement.Resolve (Mono.CSharp.BlockContext ec) [0x00000] in :0

at Mono.CSharp.Block.Resolve (Mono.CSharp.BlockContext ec) [0x00000] in :0

at Mono.CSharp.ToplevelBlock.Resolve (Mono.CSharp.FlowBranching parent, Mono.CSharp.BlockContext rc, Mono.CSharp.ParametersCompiled ip, IMethodData md) [0x00000] in :0

please help o_O... wth are those errors...