I agree I should keep an eye on the versions for this table. Being third party code I'm not exactly sure about the usage of the table but it's roughly something like two updates every 5 seconds, in separate transactions.
I forgot to mention we're using Firebird classic. When we've had the unresponsive table problem, we've shutdown our system and are left with only one connection to the problem database. The pid for this connection cannot be killed, even with "kill -9". This I don't understand. Does anyone know why a "kill -9" would not work and what sort of state Firebird has gotten into? Thanks, Greg