[CentOS] Problems running programs compiled unter Centos 5 on Centos 4 machines

I know this is quite a handwaving, stupid question, but I don't know
where else to ask it and maybe somebody here can at least point me
into the right direction, because I'm stuck.

I have a program package that were using here (OpenFOAM for those who
know it). My problem is that when I compile and link this package on
CentOS 5, it won't run on CentOS 4.x-machines but stops with a
floating-point-exception. The funny thing is that my experiments with
strace and gdb indicate that the problems occur during the loading of
an .so (that does not belong to the package). I was able to remove
that so from the build, the program then failed with similar symptoms
at another library.

Has anyone here seen similar behaviour and what would be a possible
solution? (to compile under 5 in such a way that it runs on 4)

My problem is, that moving all machines to CentOS 5 is not possible,
because our cluster-solution (Rocks) is based on 4.

Any hints (how trivial they may appear to you) are most welcome.