Cannot Reply or Comment Tickets

I’ve recently had some trouble getting into the ticket reply/comment
screens for existing tickets. I can view existing tickets, but when
clicking on the [Reply] or [Comment] links, the page starts to load, but
then quits. It gets as far as the “Status” drop-down box, and then it
dies. The last thing it displays is the word “Owner”, but the drop-down
box for the owner never appears. Any ideas what could cause this kind
of behavior?

RedHat 7.2
MySQL 4.0.13
Apache 1.3.27
RT 3.0.10

Dan Clark
Internet Technology Specialist