JDBC Driver NOT throwing Exception

Has anybody ever seen a situation where the database is rollback
transaction (due to resource limits being bust) but the JDBC Driver is
NOT throwing an exception!!!!

The system is writing approax 300 inserts per second, very little
reads.  for the first ten minutes the database runs fine.  Then it
busts a buffer limit and starts rejecting inserts and writing to the
windows event queue.  But the JDBC driver is unaware there is a problem
and is reporting that the correct number of rows have been inserted.

We are using SQLServer 2000sp3.