Urgent Help Needed.

Hi fop Xperts,
I am printing pdf using apache fop on Enhydra app server.
Once I have restarted the server its printing pdf correctly for 5-6 times.
After that it becomes too slow and not able to generate it. I am using fop
0.2 version (I am using RenderFOP class for rendering). 
Can anybody please guide me. what could be the problems?

Thanks & Regards
Purvesh Vora