Can I run a RedHat 7.3 binary on SUSE 9.3 ?

I've heard that linux binaries are not portable, but I'm not sure what exactly is meant by this. If I have a statically linked binary, would it have a good chance of running on another linux distro? My app is an old RedHat 7.3 gui that uses wxWidgets, and I might need to port it to SUSE 9.x. I was curius if it should run "as is", maybe by just supplying any other Redhat binaries it expects to find. When I google "portable linux binaries", the stuff I find makes it sound like this wont work. Yet, I believe nVidia (and perhaps others) release a "universal binary for linux". So maybe it does work? Any suggestions? thanks!