DS V8.51and BM3.5 Abends Server

I have a NW5.1 server w/SP4, DS v8.51 and BM 3.5 with the latest service pack. The problem is that it abends about every 2 to 4 days with the following abend error:
Fatal Exception (number 14, cause Abend:Page Fault running process:NLSLSP thread 48 code executing in module DS.NLM v8.51 at offset +8876eh)

I have 2 other NW 5.1 servers one with SP4 installed and one with SP3, no problems.

The BM server also gets BM Licensing errors during a shutdown. I have tried removing all BM licensesand re-installing them but to no avail.

Otherwise the BM server works great, users can get to the internet, check email, etc...

DSrepair and Vrepair both report no errors.

I couldn't find a good answer on Novell's site.
Any help is appreciated!

Thanks