umbraco contour v 30.13 install fails-Collection of common programming errors

OS Name Microsoft Windows 7 Professional Version 6.1.7601 Service Pack 1 Build 7601 .net framework 4.0 Visual Studio 2010

I have tried adding Contour to this site several times, any Ideas on what I can do to get the latest version installed

Could not load type ‘System.Runtime.CompilerServices.ExtensionAttribute’ from assembly ‘mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.TypeLoadException: Could not load type ‘System.Runtime.CompilerServices.ExtensionAttribute’ from assembly ‘mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.

Source Error:

Line 29: 
 Line 30:     
Line 31:     
Line 32:         Line 33:     

Source File: c:\Visual Studio 2010Projects\PlanetSupersaver\umbraco\Masterpages\umbracoPage.Master
Line: 31

Stack Trace:

[TypeLoadException: Could not load type ‘System.Runtime.CompilerServices.ExtensionAttribute’ from assembly ‘mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.]

System.ModuleHandle.ResolveType(RuntimeModule module, Int32 typeToken, IntPtr* typeInstArgs, Int32 typeInstCount, IntPtr* methodInstArgs, Int32 methodInstCount, ObjectHandleOnStack type) +0 System.ModuleHandle.ResolveTypeHandleInternal(RuntimeModule module, Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext) +180

System.Reflection.RuntimeModule.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments) +192

System.Reflection.CustomAttribute.FilterCustomAttributeRecord(CustomAttributeRecord caRecord, MetadataImport scope, Assembly& lastAptcaOkAssembly, RuntimeModule decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, Object[] attributes, IList derivedAttributes, RuntimeType& attributeType, IRuntimeMethodInfo& ctor, Boolean& ctorHasParameters, Boolean& isVarArg) +115

System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType, Boolean mustBeInheritable, IList derivedAttributes, Boolean isDecoratedTargetSecurityTransparent) +426 System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeAssembly assembly, RuntimeType caType) +103

System.Reflection.RuntimeAssembly.GetCustomAttributes(Boolean inherit) +33 System.Web.UI.AssemblyCache.GetAjaxFrameworkAssemblyAttribute(Assembly assembly) +73 System.Web.UI.ScriptManager.get_DefaultAjaxFrameworkAssembly() +378

System.Web.UI.ScriptManager..ctor() +24

ASP.umbraco_masterpages_umbracopage_master.__BuildControlScriptManager1() in c:\Visual Studio 2010Projects\PlanetSupersaver\umbraco\Masterpages\umbracoPage.Master:31 ASP.umbraco_masterpages_umbracopage_master.__BuildControlform1() in c:\Visual Studio 2010Projects\PlanetSupersaver\umbraco\Masterpages\umbracoPage.Master:30

ASP.umbraco_masterpages_umbracopage_master.__BuildControlTree(umbraco_masterpages_umbracopage_master __ctrl) in c:\Visual Studio 2010Projects\PlanetSupersaver\umbraco\Masterpages\umbracoPage.Master:1 ASP.umbraco_masterpages_umbracopage_master.FrameworkInitialize() in c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\7c7d6412\97bad0a\App_Web_umbracopage.master.a29f75f4.t9utysjw.0.cs:0 System.Web.UI.UserControl.InitializeAsUserControlInternal() +35 System.Web.UI.MasterPage.CreateMaster(TemplateControl owner, HttpContext context, VirtualPath masterPageFile, IDictionary contentTemplateCollection) +1019 System.Web.UI.Page.get_Master() +55 System.Web.UI.Page.ApplyMasterPage() +15 System.Web.UI.Page.PerformPreInit() +47

System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1070