Java EE (Java Enterprise Edition) General Discussion

I keep getting this error and I cannot figure out why???
Is this error generic or is it specific??
I have a simple program that checks the tag name of the first element in a xml file. It runs fine on my local machine, however when I put it on the server and access it via a servlet it throws that exception. I use the same xml file that I tested it with on the local machine so if it works on the local machine with that same file but breaks on the server, what could it be???
If anyone has any suggestions I would appreciate it, cause this has been bugging me.
Although the code is rather simple I can still post it if needed.

thank you,
Peyman M.