FIX: File Not Found on NewDwp.aspx in SharePoint when adding a web part

Receiving the following error in SharePoint or MOSS when you try to add a web part?

File Not Found. at System.Signature._GetSignature(SignatureStruct& signature, Void* pCorSig, Int32 cCorSig, IntPtr fieldHandle, IntPtr methodHandle, IntPtr declaringTypeHandle)
at System.Signature.GetSignature(SignatureStruct& signature, Void* pCorSig, Int32 cCorSig, RuntimeFieldHandle fieldHandle, RuntimeMethodHandle methodHandle, RuntimeTypeHandle declaringTypeHandle)
at System.Signature..ctor(RuntimeMethodHandle methodHandle, RuntimeTypeHandle declaringTypeHandle)
at System.Reflection.RuntimeMethodInfo.get_Signature()
at System.Reflection.RuntimeMethodInfo.GetParameters()
at Microsoft.SharePoint.WebPartPages.SPWebPartSerializer.GetPersonalizableProperties()
at Microsoft.SharePoint.WebPartPages.SPWebPartManager.GetEffectiveWebPartType(Type webPartType, SerializationTarget serializationTarget, Boolean ignoreSupportsAttributeMarkup)
at Microsoft.SharePoint.WebPartPages.SPWebPartManager.GetEffectiveWebPartType(Type aspWebPartType, SerializationTarget serializationTarget)
at Microsoft.SharePoint.ApplicationPages.NewDwp.Page_PreRender(Object sender, EventArgs e)
at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
at System.Web.UI.Control.OnPreRender(EventArgs e)
at Microsoft.SharePoint.WebControls.UnsecuredLayoutsPageBase.OnPreRender(EventArgs e)
at System.Web.UI.Control.PreRenderRecursiveInternal()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

This problem stems from two things: a) You are using the SmartPart web part, AND b) You do not have ASP.NET Ajax installed on the SharePoint server.

To correct this problem, download and install ASP.NET 2.0 AJAX Extensions 1.0 from the Microsoft site:

You may need to restart IIS on the portal server.

About the Author