Tyknapp, you most likely have one of two possible problems.
The map name is not named, under scenario properties. If this is the case, then your map is in the list, but is a blank line, that is selectable. If it is your most recent added map, it should be at the bottom.
Possibility two, is your map and containing folder are named/format incorrectly. Spaces, parenthesis, and special characters are not recognized correctly in the exporting process.
Example: "Your Map Name 6p\Your Map Name 6p.sgb"
The first half is the folder name, after the \ is the file name, this file would not export correctly.
Correct Example: "Your_Map_Name\Your_Map_Name_6p.sgb".
The use of _ to replace spaces and parenthesis corrects the error. Just open your map, "save as" the correct name format, in a dedicated folder with the exact name as the file.
You should be able to use windows paint, but I don't know if it has the ability to save as the correct format. getpaint.net is a good alternative, and GIMP as well. GIMP would be closer to photoshop, but is free, but be aware, I've encountered "problems" when downloading gimp. I have a *.edu email address, so I just purchased photoshop for cheap, and it works for me.
There are only 2 teams. A mod would be needed to add a 3rd team. There is talk of mod support in the near future though. Assigning a unit to World would leave it completely neutral, and wouldn't attack either team.
So i completely loaded a new atmosphere setting, and it still seems to glow a little, but since its day light, it is not as noticeable. I'm not sure what setting does that, but its not a big concern of mine. If you run across it, let me know.
It must be something in the atmosphere settings. I'm using a modified version of a premade, to include rain, and nighttime. Thanks for the clarification!
So this is what Ive come up with, in regards to both suggestions...(workshop updated with a few tweaks not shown in screenshot, for pathfinding fixes.)