I still got errors after upgrading the OS, but since replacing the
RAM the system has been rocl solid (crosses toes).
Just FYI, both system that i have - the one that is now toast - and the one that is showing symptoms have the upgraded RAM. Another system that does not have the upgraded RAM has never had a problem (my toes crossed too). I think i might try that OS rev - i've been stuck on 5.1.2P2 because of NIS problems - but i turned NIS off in a fit of frustration a few weeks ago...
Thanks everyone for the info you've mailed on this problem - i will summarize when the problem is (hopefully) solved.
Graham