Find Error of DLL at Client Side

hi friends

 i am using asp.net 2.0 using vb with ajax 1.0 and javascript

i make dll and send to client

but when  error comes in dll at that time i can not get the error coz client get 500 error

and actual error seen on client [server machine]  and client every time goes to server pc to see the error and then reporting to us.

so is there any way to analise the error at our end or client pc
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