Error configuring error response [890F]

My POA locks up and this error seems to be showing up about same time as the lock up. Any thoughts? I cannot login with a GroupWise client but the server is up and accessiable. Also the POA service is started but cannot be stopped. No errors in the Windows Eventlog.

Action items:
I am moving my backup times to later period from 1:20 a.m. to around 4 a.m. I also have a daily structural check/fix going on at 2 a.m. If moving the backups does not help, I will move this as well. I have 8 postoffices but only about 4 seem to have the problem and it is not every night. I had left the structural check/fix turned off for a week and we seemed to have less problems. I may consider doing it just weekly if I can isolate it as the problem (or a problem).

GroupWise 8.0.1 HP1
Windows 2003 R2 w/SP2
Happens only after midnight and usually between 2 a.m. and 5 a.m.
DBcopy is run at 7 p.m. (last a few hours)
Tape backups start around 1:30 and finish around 2:15 a.m. (we exclude the postoffice folder).