I just ran into this myself and got an explanation of it.
Im sure you dont have this problem any more but someone else
might run into this so:

SERVER-X-1345: FreeObject detected corrupt preceeding redzone
for object number.
Explanation: Memory might be corrupted.
Action: Replace memory or contact your support provider.

Try running a memtest.
Got the message on a NW6 NCS 1.6 IBM 345 servers


David Ravenna

> Hi,
> Got a NW6 SP4 cluster running with GW6.5.0 (MTA/POA/GWIA).
> On the console of the node running GW i can see this message:
> Free detected corrupt trailing redzone for node 0x9BE6B0A0, node size 88
> The server does NOT abend.
> Is this a critical error ? any fixes ? do not see one on the support
> website....
> regards,
> Jan Wiersma