We actually get this type of questions a lot. The basic answer is that we only support and validate the systems listed at http://www.pgroup.com/support/install.htm#release_info. For systems that are similar to one of the supported systems, similar meaning that they have the same kernel and glibc, more often than not the installer will also be able to install on these systems. However, when a major change to the kernel and/or glibc occurs, then traditionally we will only be able to support this new OS with the next compiler release.
We are in the process of installing Fedora Core 3 for internal testing. I’ll investigate in the coming weeks if it’s possible to adjust the installation to have the compilers work on Fedora Core 3, or if the glibc has changed too much to be compatible with 5.2.