Response receives following error while calling a WebService: (500) Internal Server Error

[HP]

I get the following error when trying to make the following call
Dim objResponse As HttpWebResponse

objRequest = CType(WebRequest.Create(strURL), HttpWebRequest)

at line

objResponse = objRequest.GetResponse()

ERROR: The remote server returned an error: (500) Internal Server Error

I tried checking the IIS and I am the other service which works ok when I
try to call
using the same code. Can you please let tme know what could be problem
on this particular webservice.

Thank you
Pat