As ltrace 64-bit doesn't know how to handle 32-bit binaries, ltrace (32-bit) should be parallel installable with the 64-bit version.
See ltrace-0.3.36-2 in rawhide. Can the customer give it a shot? My testing so far showed good results. If this works for them, we can still put this into RHEL4 GA and maybe RHEL3 U5.
Just to clarify, the version of ltrace currently in rawhide should be able to "ltrace" both 32 and 64 bits versions of the binaries.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHEA-2005-272.html