Java Development Tools

hello all
i am facing some problems with the session timeout.i have a bc4j
JSP application deployed to Apache http server that comes with
Oracle 8.1.7
the applicatin runs fine sometimes,sometimes it suddenly gives a
null pointer exception.
i set the session timeout in zone.properties files to 30
mins,even ten while i am using the application,it keeps giving
me a NullPointerException.If i logout and login again ,the
application runs fine.not one problem can be reproduced.
if i check error_log file i see the following:
BC4J HTTP Container timed out
The binding listener for AppModule was timed out.


please help me.this is creating lots of problems for me.
Thanks
Mangal