Hello,
To ensure that Informix is running, use:
onstat -
It should show something similar to following:
IBM Informix Dynamic Server Version 9.40.FC4 -- On-Line -- Up 394 days 11:16:30 -- 575456 Kbytes
If it shows something like shared memory not initialized, then it means informix is down.
Attach the copy of message log file and also paste the error when you try to create stores databases.
Bye
Nitin