download the fedora core 5 rescue cd, burn it to a disk, and boot it up. at the boot prompt, hit enter.
fill out the first two questions as needed. then say "no" to keep network interfaces down. enter "Continue" so you can edit your files. press OK next. then type:
press l (as in "log") until the cursor is right of the last colon (
. press "c$" (without the quotes) and type /bin/bash. press escape, and type ":wq" (again without the quotes). eject the CD and press Control-Alt-Delete. when your system reboots, you should be able to log in as root.
What went wrong:
chsh means "Change Shell". when you pass -s as an argument, it assumes the next argument is the shell you want for the current user.
chsh user means "change user's login shell", and I think that is what you meant.
I don't know about squid, sorry.
EDIT: I see I replied seven minutes too late.