Iwproxy error when previewing files

System

Hi i am getting an error message when previewing files in ts6.5.I have attached the screen capture of the error message.

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Connection Failed
iwproxy was unable to open a connection to:myservername.mydomain:81
reason:no reason
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I have check my default website is running port 81 under IIS.What could be wrong.This is a new installation.I install win2000,IIS,SP4,TS6.5

system spec is Win2000 SP4

Thanks.