I thought I had this one licked about a week ago, however it has come
back with a vengence.
The server is NW6.5 SP6 with patches.
Named.nlm is Version 6.05.02 August 11, 2006
I thought that I had fixed it by deleting the DNS server object with the
management console and re-creating. It worked without problem for a
week or so. Now named will stay loaded for about 10 or 15 minutes and
then exits with the assertion failure, an excert from named.run is as

Nov 05 11:07:01.000 general: main: critical: mem.c:672:
INSIST(ctx->stats[size].gets > 0) failed
Nov 05 11:07:01.000 general: main: critical: exiting (due to assertion

I tried the delete and recreate solution again a few times this morning,
however this time no change.
I am somewhat at a loss as to where to go with this one from here, any
help is greatly appreciated.