SET PDQPRIORITY error

I recently installed 7.23.UC1 on an HP9000 V-class box running HP/UX 11.0. When I issue the SET PDQPRIORITY command, with either a numeric or symbolic option (SET PDQPRIORITY HIGH or SET PDQPRIORITY 100) using low, medium, high, or numberic values from 1 to 100 I get unknown error message 874 Checking this error text I am told that this is an internal optimizer problem and to call technical support. I called tech support, and as usual they haven't got the faintest idea what could be wrong; suggested run update statistics. I don't see how update statistics could be affecting pdqpriority, but I went ahead and updated stats on all critical columns/tables anyway - made no difference. Any ideas? This is a serious problem - am getting performance on the V system (4 CPU 2 GIG RAM) only slightly better than we had on the D system (2 CPU 1 GIG RAM) it replaced. Thanx Ray Garrison