Payables Psoted Invoice register Completes with Warning for Aug-12 and later

We are running the Payables Posted Invoice Register and it will run fine for each individual month Jan-12-Jul-12 however when we run from Aug-12 to Dec-12 indicidually it completes with a warning with the followign message from the log file

+------------- 1) PUBLISH -------------+
Beginning post-processing of request 9507691 on node TLPORA01 at 09-APR-2013 16:24:45.
Post-processing of request 9507691 failed at 09-APR-2013 16:25:28 with the error message:
One or more post-processing actions failed. Consult the OPP service log for details.
+--------------------------------------+

+------------- 2) PRINT   -------------+
Not printing the output of this request because post-processing failed.
+--------------------------------------+


Finished executing request completion options.

+---------------------------------------------------------------------------+
Concurrent request completed