These are the steps I'm trying to follow.
Root Kindle Fire HD Step 4: Open up a Terminal, at the Terminal window ($ command >prompt) type:
Enter your Root Password if requested to do so. You should now see a # at the command >prompt.
The password I enter for any sudo commands doesn't work. I entered the 32 character master password that I created when I installed this version of Ubuntu 12. I tried a bunch of passwords that I've never used on this computer. "root." I don't know what else to try.