GW 6.5 POA Will not load

[Database Administrator]

I get a warning box that says

Memory error. Memory
function failure (8101).



The bottom of the POA Screen says

Checking Post Office Directory Structure ...

On the server console there is a message that says

9-11-2007 11:37:51 am: SERVER-5.0-834 [nmID=2000D]
Free detected node 0xBE755DC0 is already free

TID -10052821 seems to be about the same problem, but I have tried to
both rename and restore the NGWGUARD.DB and the problem still occurs.

Clients can access the PO in direct mode ok, but that is risky.

Any ideas? Thanks.