How can I load the DB2 JDBC Driver ??????

Hi together, this error was thrown after i tried to connect to DB2 database with a SessionBean:
---
java.lang.ClassNotFoundException:COM.ibm.db2.jdbc.app.DB2Driver
---
Does anyone know how to load the Driver
Additional Information:
i copied my driver-file(db2java.zip) into the
<j2ee home>\lib\system directory,that didn't work
then I renamed the file into db2java.jar, that also didn't work.
In both cases i set my j2ee_classpath to that file
WHAT'S WRONG !!!
Thank you
HowyC