Internal compiler error. See the console log for more information. output was: Help

Internal compiler error. See the console log for more information. output was:
Unhandled Exception: Mono.CSharp.InternalErrorException: Assets/Photon Unity Networking/Plugins/PhotonNetwork/SocketUdp.cs(28,16): ExitGames.Client.Photon.SocketUdp.SocketUdp(ExitGames.Client.Photon.PeerBase) —> System.TypeLoadException: Could not load type ‘System.Runtime.Versioning.TargetFrameworkAttribute’ from assembly ‘Photon3Unity3D’.

at (wrapper managed-to-native) System.MonoCustomAttrs:GetCustomAttributesInternal (System.Reflection.ICustomAttributeProvider,System.Type,bool)

at System.MonoCustomAttrs.GetCustomAttributesBase (ICustomAttributeProvider obj, System.Type attributeType) [0x00000] in :0

at System.MonoCustomAttrs.GetCustomAttributes (ICustomAttributeProvider obj, System.Type attributeType, Boolean inherit) [0x00000] in :0

at System.Reflection.Assembly.GetCustomAttributes (System.Type attributeType, Boolean inherit) [0x00000] in :0

at Mono.CSharp.TypeManager.IsThisOrFriendAssembly (System.Reflection.Assembly assembly) [0x00000] in :0

at Mono.CSharp.Expression.IsAccessorAccessible (System.Type invocation_type, System.Reflection.MethodInfo mi, System.Boolean& must_do_cs1540_check) [0x00000] in :0

at Mono.CSharp.PropertyExpr.DoResolve (Mono.CSharp.ResolveContext ec) [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.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.ExpressionStatement.ResolveStatement (Mono.CSharp.BlockContext ec) [0x00000] in :0

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

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

at Mono.CSharp.If.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

— End of inner exception stack trace —

at Mono.CSharp.TypeContainer.EmitConstructors () [0x00000] in :0

at Mono.CSharp.TypeContainer.EmitType () [0x00000] in :0

at Mono.CSharp.RootContext.EmitCode () [0x00000] in :0

at Mono.CSharp.Driver.Compile () [0x00000] in :0

at Mono.CSharp.Driver.Main (System.String[ ] args) [0x00000] in :0

Its not my player settings the API thing

http://forum.exitgames.com/viewtopic.php?f=6&t=523