Ubuntu :: Installed On G3 IMac, But Saying "Mount Of Filesystem Failed"?

I got it to install initially, but when I tried to edit the xorg.conf file (looking for the "Modules" sections), it came up blank, so I skipped that part.

Ubuntu installed okay but was SO slow and the graphics are not great ( I think because I was supposed to edit the xorg.conf file)

I can't really get it to run anything, and more than half the time it won't even start up. It just gives me the error:

Mount of File system failed
The maintenance shell will now be started.
Control-D will terminate this shell and retry
root@ubuntu:~#

I've created an alternate cd of Xubuntu thinking if I could install it I could maybe get the iMac to run faster...or at all...but I can't figure out how to get it installed. Do I need to uninstall Ubuntu first?

When I try to boot from cd, I get this:

First Stage Ubuntu Boostrap

Press l for GNU/Linux,
Press c for CDROM.

Stage 1 boot:

if I hit c, it takes me in a continuous loop of that screen until it freezes. (Booting CDROM...)

If I leave it alone or hit l, it takes me to the default:

Welcome to yaboot version 1.3. 13
boot:

I have two options, Linux and old...I haven't tried old...but if I enter Linux, or just let it go there itself, it tries to boot Ubuntu, but gives me the "mount of filesystem failed" error.

at the moment it's saying:

root@ubuntu:~# podif[517]: can't read sid from 520/stat

I'm trying me best to figure this out, but I'm at a loss. My husband wants to me to stop trying, but I'd really love to make it just work.