First off -- don't panic! This can be fixed, probably, but it's going to take a little work. There's no such thing as an initr, does the message say it's missing an initrd, as MichaelK suggest, or is it missing the init (the actual first non kernel process)? It's very important to get the error message exactly correct, because the problem is different in each case.
Anyhow, do you have a boot floppy? If not, maybe acquire tomsrtbt from http://www.toms.net/rb/
which will at least get you into your system. Unfortunately, tomsrtbt does not seem to have mkinitrd installed, but if it detects your network card (and it should be able to, at least that was my experience when I had to try to recover a majorly hosed system with it, a couple years ago) you can probably yank the kernel and init packages off of FTP and reinstall them (or extra the files you need and put them in place yourself).
Also, is it possible you did something silly like changing your partitions or swapping IDE cables or something that would cause your partition table to no longer be correct?