Cannot set a value of Type '{1}', for a field described by TypeDescriptor with TypeName of '{2}', which resolves to .Net ...

Cannot set a value of Type '{1}', for a field described by TypeDescriptor with TypeName of '{2}', which resolves to .Net type '{3}'. This TypeDescriptor is named '{0}' and is on Parameter '{4}' of Method '{5}' in Entity (External Content Type) with Namespace '{6}' and Name '{7}'.