I think I have an idea if u have a Tape or a Floppy Drive, Looks logical but never tried.

1. Boot the node through the Install CD ==>>Open Recovery Shell ==>

loadfil /usr/bin/ps
loadfil /usr/sbin/insf
loadfil /usr/sbin/tar
loadfil /usr/sbin/ioscan
insf -e
ioscan -fnCtape
tar cvf /dev/rmt/0mn /usr/sbin/ps

Boot the system normally and restore this tape !

Regds,

Kaps