PemGen error on JSAS 9.0

Hi all I am running Sun Java System Application Server Platform Edition 9.0 for test development of a struts project. Periodically I run into an error along the lines of PermGen error (I can't read the full stack trace as the page doesn't display correctly. I was wondering if anyone might be able to give me ideas as to how to determine the cause of that error.

thanks in advance

[395 byte] By [Aknibbs] at [2007-11-26 10:11:36]