Yes it is the only app.

The thing I'll point out is that you say you're using RHEL 5.7 (bolded for emphasis).

You do realize that RHEL 5.7 is ancient, right? Totally unsupported/unpatched and EOL, and has been for a LONG time now. If you're installing a new version of Peoplesoft, it's very possible that it's doing things badly, based on the age of your system. You've got VERY old libraries/kernels. First thing you need to do is get onto a current version of RHEL (if you're PAYING for it, that is), or load CentOS if you're not.

Personally, I'd load the latest CentOS onto a spare system, load up Peoplesoft, and see if the problem follows. Should be easy to log in a few folks to see what happens, and you can do all that for free. And you really should contact Oracle support.