Informix MULTIPROCESSOR cannot be set to 1 after upgrade from AIX5.2ML02 to ML06

Hi there, I met a strange problem here. I have 13 database instanse in one 690 machine. Last week, I upgrade my OS from AIX5.2ML02 to ML06 as IBM suggest. After that I find there are two instanse cannot startup, and reporting the following error: 10:25:29 IBM Informix Dynamic Server Version 9.40.FC3W3 SoftwareSerial Number AAA#B000000 10:25:29 listener-thread: err = -27100: oserr = 9: errstr = : InternalCommunications Error: NSF subsystem error. System error = 9. 10:25:29 sql_listener: ASF_LISTEN failed Check the setting and tried many times, find if I set MULTIPROCESSOR from 1 to 0, and NUMCPUVPS from 3 to 1, it works! Another test is if MULTIPROCESSOR and NUMCPUVPS remained original, I delte the DBSERVERALIASES, the instanse can start, but cannot be access. Does anybody meet the same problem?