I had two main problems. As mentioned, I was trying to use Mapsource with an image file and was trying to program the Garmin via software. I didn’t realize the PC recognized the unit as a HD. Everything fell into place after I got those things straight.
The fast IMG Unlocker is quick, easy and works great. One thing to note, the software will only unlock one file at a time. Not a big deal unless you don’t know about it. The unlocker must be placed in a folder with only one image. If placed with multiple images, it will only unlock the first one it sees.