using too much soap?

I'm running a loop on acomputer that repeatedly calls a Client program
which, in turn, accesses a remote service over and over again. And it
works fine for about the first 10-20 iterations. Then I get "Exception
from service object: null" over and over. If I restart the remote soap
service, it starts to work for a while before crapping out again. 

Even weirder is that after it starts crapping out (regardless of
restart), every 50 or so times, it'll work properly, then go right back
to sucking. 

I think I'm either overloading Tomcat (5.0.12), SOAP, or mysql. Can
someone guide me to which one it probably is?

Cyrus