ntop problems with FreeBSD?

[adp]

Anyone get ntop totally working with FreeBSD 4.9? We can run it, but it's
flaky. On one FreeBSD box it runs fine for a while and then just dies. No
syslog messages. It's just gone. On another it won't display anything in the
Web interface (it opens new windows when clicking on some items), and it
also randomly crashes. We are using ipf on one system and ipfw on another.
All are dual-homed FreeBSD firewalls.