I finally had a chance to try an install on RH 5 x64 since it is now supported in 4.3.1. I have done some installs on Windows and RH 4 i386 and had no issues, but the 64 bit threw a couple problems.
1. The setup_linux_intel.bin file did not handle x64. When you ran the script the message "OS not supported" would be displayed. To correct this problem look for the case statement "case `uname -m` in" under this there is not a check for a return of 64 bit. So I modified the case to look like:
case `uname -m` in
*) echo "OS not supported."
Once this was done, the installer would start.
2. With the setup_linux_intel.bin fixed I was now getting the message "The installer is unable to run in graphical mode. Try running the installer with the -console or -silent flag". I made sure I had all the prereqs according to the doc, but still nothing. So after some playing around, I found out that I was missing the libraries libXmu-1.0.2-5.i386.rpm and libXp-1.0.0-8.1.e15.i386.rpm. The 64bit versions were there but not the 32 bit.
Hopefully this saves someone some grief if they need to install on RH5 x64.