Bind 9 becomes unresponsive

I just upgraded our bind 8 configuration to bind 9.3.1. Bind will stop
answering quieries with the following error in syslog:

named[27140]: [ID 866145 daemon.crit] mem.c:1607:
INSIST(mpctx->allocated > 0) failed

This is running on a Solaris 9 server that is way beefier than what
should be needed for DNS. It's a Sunfire V240, 8G of ram, dual
processor machine. I have bind running in a chrooted environment, and
I built it with gcc version 3.4.1. I have run named-checkconf against
my named.conf, which resulted in no errors. I have also run
named-checkzone against my zones and again it resulted in no errors.
The server will stop responding at random times, and initially seems to
perform normally.

Any ideas?