I checked with my lone netware client. They run 6.5.2NW with psql 8.6 & macola 76300a, exclusively using PWE. Life is good and stable. He is having many problems applying NWsp6, and thinks he may have to apply sp5 first. It sounds like the NWsp6 is the problem. If you have macola support or your reseller can place a call, it's worth asking if anyone else has reported. I don't see anything in infomine re: this issue. Officially, macola no longer supports psql 8.6, but they usually will answer questions about it. Other than that, if you, too, are experiencing problems applying sp6 properly, maybe it is a novell question. There is also a pervasive discussion forum on their website and pervasive group on this website where you might find some information. I remember when I installed 8.5 on this netware server I had many problems, and macola told me right away to upgrade to 8.6.
Post back with your results since we don't have that many netware users anymore. Your experience can help the rest of us get through it.