Well, it looks like I have to work on each mission one by one. On the SB website, sSnake and others posted a method on how to work on this. Goes something like this:
#1: go to map editor and click on default maps. From there, upload the old map used in the mission and publish.
#2: if #1 doesn't work, extract the mission and install a new map and go from there.
#3: well, I didn't get this far.
All in all, it's a process. If there was a way to do it all right the first time, I failed miserably. I have managed to successfully run a few missions that would not work the first time. Had that pop up window that said something like, "Cannot find the legacy map this scenario is based on. The terrain map is called X, the height map is called Y." Then it lists three options. I used the first two options and the specific missions loaded successfully.
Am I doing this the difficult way?