assert failed:condition failed (Bad pool pointer 0xc0000000393b6028), In (mt_shm_malloc)

I don't understand this problem. When I killed tha session 73755 the sistem down. But the session 73755 is a program ESQL than run all the time each 5 minutes, and rarely I had this problem. The session 74661 is a simple select query 8:11:38 Assert Failed: Condition Failed (Bad pool pointer 0xc0000000393b6028), In (mt_shm_malloc) 08:11:38 Informix Dynamic Server Version 7.31.FD3W1 08:11:38 Who: Session(74661, sisteca@luz001, 21846, 891564248) Thread(135333, sqlexec, c000000034fa2af8, 3) File: mtshpool.c Line: 2702 08:11:38 Action: Please notify Informix Technical Support. 08:11:38 stack trace for pid 13475 written to /tmp/af.148d9209 08:11:38 Assert Failed: No Exception Handler 08:11:38 Informix Dynamic Server Version 7.31.FD3W1 08:11:38 Who: Session(73755, luz@linluz001, 12028, 970342680) Thread(134325, sqlexec, c000000034fb1cb0, 1) File: mtex.c Line: 454 08:11:38 Results: Exception Caught. Type: MT_EX_OS, Context: mem 08:11:38 Action: Please notify Informix Technical Support. 08:11:38 stack trace for pid 13472 written to /tmp/af.109d9209 08:11:45 See Also: /tmp/af.109d9209 08:11:45 mtex.c, line 454, thread 134325, proc id 13472, No Exception Handler. 08:11:45 PANIC: Attempting to bring system down I'm using informix 7.31FD3W1