Internal Compiler Error

I really need help with this. I have an error that's coming from the scripts in the first person controller: Mouse Look, Character Motor, FPSInput Controller, and Mouse Look (in camera). This is the error:

 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

I've heard that the problem comes from leaving MonoDevelop open after starting a new project (which I did), but I need to know how to fix it. I can't run the game if this error remains. Also, on every script component in my FPS Controller, it says "The associated script can not be loaded. Please fix any compile errors and assign a valid script."