After R12.1.1 Upgrade Concurrent Managers Won't Start

 We tested an upgrade from 11.5.10.2 to 12.1.1 and database upgrade from 10.2.0.4 to 11.2. on Windows Server 2003.  We have finished the technical upgrade but are now troubleshooting an issue with concurrent managers.  Some managers such as Internal Control and Service managers can start.  The rest simply won't run at all.  In our analysis, it looks like the managers cann't make a connection to the database so it could be a network configuration issue.  However, we are out of ideas as to how to fix this problem.  So any idea and suggestion would be very great at this point.

Thanks, Paul