FXCop assembly load failure

Question

Command line:

 "C:\Program Files (x86)\Microsoft Fxcop 10.0\FxCopCmd.exe" /file:XXX.exe /out:fxcop-report.xml /outxsl:none /forceoutput /searchgac /assemblyCompareMode:StrongNameIgnoringVersion /verbose 

Error from report:

   <Type>Microsoft.FxCop.Common.AssemblyLoadException</Type>
   <ExceptionMessage>Could not load XXX.</ExceptionMessage>
   <InnerType>Microsoft.FxCop.Sdk.InvalidMetadataException</InnerType>
   <InnerExceptionMessage>The following error was encountered while reading module 'XXX': Security attribute type does not have a default constructor: System.Security.Permissions.SecurityPermission.</InnerExceptionMessage>

Anyone any ideas?