perl-Font-AFM package is not available for EL-4. Rebuilding the EL-5 srpm works just fine.
Xavier, Do you still want this for EL-4?
Most likely not. This is probably a left over from when I was working on pushing RT3 to EPEL. The EL4 perl stack is too old for a number of modules, and I've not much interest in EL4 anymore anyway.