I tried to use a store procedure to launch 4ge program and got the following error message:

-668 System command cannot be executed. A system call failed in the operating system. The following example shows a statement that might cause an error: SYSTEM
'hello';

-1 Not owner. An operating-system error code with the meaning shown was unexpectedly returned to the database server. Check the ownership and permissions of files and directories that are used in the current operation. Look for other operating-system error messages that might give more information.

I can launch 4ge program from command line without any problem, and the attribute for the 4ge program is :-rwxrwxrwx.

Any idea?

The system command will be executed by the user who started the informix server.
ps -ef |grep oninit will show you that user.

Make sure your 4GL executable has execute permissions for this user.

woeps, sorry about that quick response...
Check the following file: system.txt

Thanks.
Finally, It looks like I solved the problem.
1. when the 4ge program is called by system comand, the environment is different.
some env variables are missing, for example, INFORMIXDIR, INFORMIXSERVER, and LIBPATH.
The command line should set those env variables.

2. Then, The store procedure should use the c shell script to launch the 4ge program. In the script file, redirect the error message to a file.