My NBM 3.91 SP1 server experiences an abend every week or two when ACLCHECK runs at its 24 hour interval.

This time I noticed the following on the console just before the abend:

5-06-2008 10:11:24 am: SERVER-5.70-834 [nmID=2000D]
Function Free received invalid pointer 0x00260000

The abend.log is attached.

The server is running NW65 SP6, 6GB RAM; using CJ's proxy.cfg and Smartfilter for category server. It's not configured for VPN.

Any idea what's going on?