Contacting DB from Web Part via Web Serivces ????

[cyrus]

Hi I am trying contact my DB from my Web Part via my Web Service but i failed
everytime,
I can contact my DB directly from my Web Part and I can contact my Web
Service from my Web Part to send or retrieve bytes, strings or ...

but my problem is when i am trying to contact my DB from my Web Part via my
Web Service then i get following message:
----------
An unexpected error has occurred.
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