Hanging processes after database startup

Hi everyone, My group has been experiencing a very strange problem with database processes hanging after starting up Informix OnLine 5.02 UC7. We're running on a UNIX box with the SVR4 operating system. Once a week, we shut down Informix, reboot the computer, and then start Informix back up. Everything appears to be working normally. There are no error messages on the console or in the Informix log files. However, when our users log on and try to enter the database applications, their database processes SOMETIMES hangs. They literally stop. The users have to close down their terminal emulators on their PCs and attempt to log on again. They may have to go through this processes two or three times before they are able to successfully run the application and get their work done. The strangest thing about this problem, besides it being intermittent, is that it tapers off after a couple of days. It occurs quite frequently the day after rebooting, less the second day, perhaps only once or twice on the third day, and then does not occur at all for the next four days, until the next reboot. This is what the hung processes look like from ps: narmus 4894 1 0 08:37:30 ? 0:00 isql liars -u main narmus 4895 4894 0 08:37:30 ? 0:00 /informix1/lib/sqlturbo A tbstat -u reveals an "S" flag next to these hung processes. Could it be a problem with shared memory latches? Some problem with the system catalog or work space? If anyone has any ideas or suggestions, they would be greatly appreciated. Thanks, Lou Avrami AT&T Law & Government Affairs