When you plug your phone into your pc with usb debugging enabled, pull down the notification bar, click usb connected, then hit the gray bar under the green droid on the screen that appears, an auto play window will pop up on your computer, click "open folder to view files", the directory that pops up is the root of your sd card. This is where the update.zip file should be. Look for it there, everything should be listed alphabetically. If it is not there you will need to find where it is and delete it from that location, then save a new copy to that first directory.
When you find those files you got from DroidXcon, make sure you saved a copy of them to your pc, then you will pick up the instructions from the first post at step 3.
I found the file in post#1277 on page 128. Bummed I can't work on this from work....grrrrrr. I have a feeling the root of my problem is the unzip file to the sdcard. Thanks a Mill for the instructions. I'll let you know how it goes after I get back home.