URL rewriting problem at server

Hello Guys
I got stuck in special problem, I did code for URL rewriting, My code is working well at local but it?s not up at server.
One strange for testing I make a sub domain and upload same file there but its working there and not working at domain.
Please click on left side menu
http://newyorkcity.partyaid.com/Lees-Party-New-York-City.aspx
is working  but
http://www.partyaid.com/Lees-Party-New-York-City.aspx
is not working does anyone know what is mistake.
Thanks
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