Customer was logged in as instance_id when he issued "ps eww <PID of db2sysc for that instance_id>". This works on all of their servers (AIX/Linux) except for SUSE 10. The only way I could reproduce this "behaviour" (no env info is displayed) is if I try to get the environment for a different user.
Anyway, there is another way of getting this info as described here:
http://yong321.freeshell.org/computer/ProcEnv.txt