how to use query masking???

hey guys,

When i am setting a query mask for my entities,then my rayscenequery()
is not working.
It is crashing while debugging the application.The exceptions are in the (Back & Front of the resultentry).
http://www.ogre3d.org/phpBB2addons/viewtopic.php?t=3062

Now friends i need this masking urgently.Can any one help me there.
How to make it work..

Thanks in advance..