I managed to get it working in the end. I did two things to get it working (I'm not sure which one is required, but I'll probably be testing this shortly):
- I installed CF5 with the RH RPM. This puts the CFIDE dir in /var/www/html. So, I changed the primary web directory to this.
- I chmod'ed everything to 0755, and chown'ed to admin.shared. I have a suspicion that this is what fixed it (including turning off the setGID bit).
I haven't had a chance to conduct full testing of this installation, but the CFIDE appears to be working. I'll endeaver to write up a short howto on this if it works. (I think the same steps will work for 4.5.1 as well).