Well you learned a very painful lesson.......... You can try the following:
Boot with the installation media into rescue mode, when the menu screen is displayed type: linux rescue
Answer a few questions and do not use the chroot command (you have no need). When ready copy both the rpm and rpm2cpio files from the /bin directory to your root's directory on the hard drive, example;
cd /bin
cp rpm /mnt/sysimage/root/rpm
cp rpm2cpio /mnt/sysimage/root/rpm2cpio
Re-boot the system normally (remove the installation from the drive if need be). After the system is done booting either mount the media and locate the rpm 4.4.2-15, popt and neon rpm packages on the media or download them from Fedora Core;
http://download.fedora.redhat.com/pu.../linux/core/5/
to your root's home directory then from the console or xterm session as root type something like;
rpm -ivh *.rpm
Example of the files you want:
neon-0.25.5-1.2.i386.rpm
popt-1.10.2-15.2.i386.rpm
rpm-4.4.2-15.2.i386.rpm
rpm-build-4.4.2-15.2.i386.rpm
rpm-devel-4.4.2-15.2.i386.rpm
rpm-libs-4.4.2-15.2.i386.rpm
rpm-python-4.4.2-15.2.i386.rpm
If you have any dependency issues for the install then satify then the same way either download them or copy them for the installation media.