'attribute' : attribute is only valid on classes derived from System.Attribute
An attribute was used that can only be used on a class that derives from the NGWS Framework's System.Attribute.
The following sample generates CS0641:
using System; using System.Interop; [attributeusage(AttributeTargets.All)] public class NonAttrClass { // CS0641 // try the following line instead // public class NonAttrClass : Attribute { } class MyClass { public static void Main() { } }