Rsd lite is a program for your pc that's used to flash sbf files to your phone. If you're using the droid forum app, you may not be able to see the links in guidot's sig. I'm mobile now, but I'll posts some links in a few. Or google "motocache1 root regardless of OS".
Not sure why thats happened, but the only way I know how to get another recovery on the D1 is to use rsd lite or flashing it through a working recovery.
The one thing I see people having trouble with rsd lite is getting the pc to detect the phone. And there's always a risk of hurting something when you do stuff like this to your phone. Just take your time and read through the instructions. If you have any questions, just let us know.
I used to have real issues with Clockwork on my Droid. Here's a writeup I did back then:
The first thing about Clockwork is trying to get Rom Manager to flash a good copy onto your phone. Here is a fool proof method to determine whether you have a good copy before trying to reboot into it. Begin by scrolling down and flashing the alternative recovery – SpRecovery. After it successfully loads, scroll up and flash Clockwork. If it takes longer than 3-5 seconds to get the popup telling you the install was successful, reflash it over and over until you do get that popup in 3-5 seconds. Once that happens, you have a good install.
Once you have rebooted into Clockwork and are navigating through its menu, if at any time it hesitates that means it is about to reboot automatically. When Clockwork does reboot and the screen goes dark, immediately press and hold the X key until the phone reboots back into Clockwork. Clockwork will now be totally stable until you finish.
If the first thing you do with Clockwork, during any particular session, is to try and make a Nandroid backup and you get an error message (without regard to what it says), you should just wait a few seconds and not do anything. That is because Clockwork is about to reboot the phone. As stated above, as soon as the screen goes dark, press and hold the X key until the phone reboots back into Clockwork. Then start over and Clockwork will work as it was intended for the rest of the session.