getting trouble with Xquery match assertion

hi
I am getting error message in Xquery match assertion as shown below.

XQuery Match Assertion failed for path [declare namespace soap='http://www.w3.org/2003/05/soap-envelope'; declare namespace ns1='Microsoft.Samples.XmlMessaging.WebServices'; declare namespace ns='namespace1';  { for $z in //ns:AddResult return  {data($z)}  }  ] : RuntimeException:java.lang.reflect.InvocationTargetException

the code
at my declaration window

declare namespace ns='namespace1';

{
for $z in //ns:AddResult
return {data($z)}
}