ORA-25253: listen failed, queue. is not enabled for dequeue

When an invoice was submitted through a request set following error appeared:

ORA-01116: error in opening database file 54
ORA-01110: data file 54: /erp11i/datafiles1/a_txn_ind08.dbf
ORA-27041: unable to open file
SVR4 Error 24: Too many open files
Additional information: 3

I asked the DBAs to check the open file descriptor limit by issuing commnad:

ulimit -n

The result was 65536 which is the max value.

I asked them to reduce it by 2 and set it to 65534 and bounce the database.

The error changed after making this change to ulimit and bouncing the DB. Now the error is:

While compiling the flexfields, the procedure wf_event.raise failed with following parameters:

event_name=oracle.apps.fnd.flex.dff.compiled
event_key = SBX.$SRS.SBXAPPROM

The error raised is
ORA-25253: listen failed, queue. is not enabled for dequeue

I have asked the DBAs to recreate the workflow queues and see if it helps.