Segmentation Violation on Online 7.20UC4X1

Hello! Our 7.20UC4X1 on Digital-Unix 3.2G had have an problem: 05:48:23 Logical Log 21373 Complete. 05:48:24 Logical Log 21373 - Backup Started 05:48:28 Logical Log 21373 - Backup Completed 05:52:01 Checkpoint Completed: duration was 3 seconds. 05:52:01 Assert Failed: Internal Error - Segmentation Violation 05:52:01 Who: Session(1, informix@saturn, 0, 164159528) Thread(7, main_loop(), 9c5a028, 1) 05:52:01 Results: OnLine must abort 05:52:01 Action: Reinitialize shared memory 05:52:01 See Also: /tmp/af.72ef1, shmem.72ef1.0 05:53:07 Error writing '/tmp/shmem.72ef1.0' errno = 28 05:53:07 rsinit.c, line 9644, thread 7, proc id 611, Segmentation Violation. 05:53:07 PANIC: Attempting to bring system down I'm not sure, what I can do and what should I do. I've followed the Log and have reinitialized the shared mem, but what is the reason for this error? Thanks for all infos.... Bye Andy M. Bettin