tbcheck: no output for some users

I have encountered a strange situation with the tbcheck utility (and only tbcheck, the other tb* utilities are fine) that I would like to know if anyone can explain. We have several (1,000+) remote sites running on 2 platforms IBM RS/6000, AIX 3.2.0, OnLine 5.0, and NCR 3350, SCO 3.2.4.1, OnLine 5.0 My situation is this: As user root or informix, when running 'tbcheck --' or any other option of tbcheck that normally results in some output, we get the expected output and an appropriate status value ($? or $STATUS). As any other user running the same commands, there is no output but the same status values are returned. I am sure that the tbchecks are being executed because of the different status values returned. Also, because if I change the $TBCONFIG value to an invalid tbconfig, I receive an appropriate error message from tbcheck. stderr seems OK but stdout is unknown. EVEN STRANGER, AT SOME SITES IT WORKS CORRECTLY FOR ALL USERS! I realize that not all users have the ability to execute ALL tbcheck options but any user should be able to display the tbcheck usage with 'tbcheck --' (which returns a status value "1"). Also, the user should be able to run the 'tbcheck -ce' option to view over-extent usage since no "fixes" are performed. I would like to identify some parameter, value, permission, flag, etc. that would explain this behavior at some sites but not others. I have examined the following areas and found no unique differences for those that work and those that don't (we strive for conformance at all sites). OS level, Informix level, groups, group ids, user ids, shells, database ownerships (user owns DB), database permissions (user is DBA), CONSOLE value in tbconfig, /tmp permissions, and $INFORMIXDIR/msg permissions. What am I missing? Any help would be appreciated. I have an open case with INFORMIX at Lenaxa and Detroit but nothing has turned up yet. A technical explanation of the tbcheck internals from Informix would be greatly appreciated. Please respond by posting or private e-mail to kroger@dialup.oar.net, Subject line "ATTN: Dave Lutz". Thanks in advance, Dave Lutz DBA, Store Systems The Kroger Co.