PSQL engine stops while Backup Agent is switched off

Hallo Btrivieans!

since a couple of weeks we observe, that sometimes - not ever - PSQL
engine 8.1
stops while Backup Agent is switched off:
Backup Agent runs twice a day, 12:30 and 20:00 a clock. Many times it work
without problm, but sometimes for some reasen I dont konow, the PSQL
engine
simple stop work: here whats in the pvsw.log-file


07-10-2007 12:35:58 W3CACHE         00000620 W3DBSMGR.EXE    TKHSERV      
  I
                      MicroKernel is using default settings.
07-10-2007 12:35:59 W3CACHE         00000620 W3DBSMGR.EXE    TKHSERV      
  W
                      Resources allocated
07-10-2007 12:36:38 W3CACHE         00000620 W3DBSMGR.EXE    TKHSERV      
  I
                      Resources released


(entries before 12:35:58 are not from 07-10-2007!)

(We have already exclude the btrieve-datafiles from virus-scanning.)

Is this phenomenon known? Will it make sense to update to 8.6 (i.e. is it
a
known issus in 8.1)?


Any hint will be welcome

Regards
Mircea