Odd error in consuming Web Service

Ok, this is really wierd. In my Photo Album Admin application I call the Photo Album WS. For one of the many web-methods in the WS, I get the following error:

An unhandled exception of type 'System.Web.Services.Protocols.SoapException' occurred in system.web.services.dll

Additional information: Server was unable to process request. --> Source and destination path must be different.

All the other web-methods work expect for one. I'm using the Microsoft WSE 1.0 SDK, but this web-method isn't doing anything WSE sepecific.

Has anyone come across this problem before? How do I go about fixing this?

UPDATE: After a little bit of debugging (NOT all this time
since my initial post!), I figured out that the problem wasn't what the
Exception above said it was. I ended up enabling the "Break into code everything
an Exception hits" in VS.net and ended up getting another error:

A first chance exception of type
'System.Net.WebException' occurred in system.dll

Additional information: The remote server returned
an error: (500) Internal Server Error.

So, I took a look at the Web Service, and indeed, there was a really odd
thing that I was doing in the code for this web-method which was throwing an odd
error. Granted, my error in the web-method is not excusable, however, VS.net
should be giving me a correct Exception that's being thrown. Most of the time
spent debugging this ended up not being finding the actual problem but trying to
debug a non-problem which the first Exception was pointing to. Anyway, this is
now in the process of being fixed.