Pls help to resolve problem with JMS topics on WAS 6.0.2

My application consists of several MDBs, wich pick messages from the same JMS topic.
MDBs call each other sending messages to this topic and reading those messages, thus creating some chain process (it fulfill custom workflow).
The problem is that during intense job (after hundreds of workflow cycles) JMS topic became "dead", i.e. after delivering message to the topic this topic don't call some MDBs, so my chain process terminates.
And there are no any error messages in SystemOut.log.

What can in be?