After recently trying to re-register a RHEL3 server that had crashed, I discussed the issue with RedHat who advised that since RHEL 3 was end of life (EOL) new servers could not be managed or registered.
Because of this, the workaround I used was to download the .iso files for RHEL3 U9 and mount them.
To mount the iso files, you can use the command below:
mount -o loop -t iso9660
Once you have mounted the iso file you can cd to $MOUNTPOINT/RedHat/RPMS and search for whatever you need.
Once you find what you need, you can install it using the rpm command.
For example, rpm -ivh RedHat/RPMS/gimp-devel-1.2.3-20.3.el3.i386.rpm
