[Jerom]

Okies, to fix those parts...
I'm going to show you how to make a map.txt.
Each level is obviously within quotations: "
Seperate each level name with commas: ,
At the end of each level line, when you want to start a new layer of levels that is, do not put a comma after the levelname:
"level1.graal","level2.graal"
"level3.graal","level4.graal"
Added
"level1.graal",level2.graal","newlevel1.graal"
"level3.graal","level4.graal"

Notice I added a level on the first line.
So your map would have 3 levels on the first(top) line, and 2 levels on the second line(bottom line in this case).