Runaway Locks

I was connecting to Postgres 8.3 through JDBC. During my unit tests, something when wrong and now leaving with the
followinglocks in the db: 

arc_dev=# select locktype, mode, relname, virtualtransaction, pid from pg_locks l join pg_class c on l.relation =
c.oid;                                            
locktype |       mode       |          relname           | virtualtransaction | pid
----------+------------------+----------------------------+--------------------+------
relation | AccessShareLock  | pg_locks                   | 1/38               | 1816
relation | RowShareLock     | hibernate_sequences        | -1/2091555         |
relation | RowExclusiveLock | hibernate_sequences        | -1/2091555         |
relation | AccessShareLock  | pg_class_oid_index         | 1/38               | 1816
relation | AccessShareLock  | pg_class_relname_nsp_index | 1/38               | 1816
relation | AccessShareLock  | pg_class                   | 1/38               | 1816
(6 rows)arc_dev=#

The locks on 'hibernate_sequences' is causing any update to the locked row to hang. There is currently no running
databaseclient process anymore (as I've restarted by server a few times). 

My question is how do i kill the virtual transaction and have the locks released?

Thanks,
kam