There are two problems; first, the file type is ".txt" when it should be ".CivBeyondSwordWBSave". The second is that the first portion of the map file is all bunched up, where it lists all the players/civilizations.
The solution to the first problem is to change the file type; go to your Saves: Worldbuilder in MyDocuments folder, find a file that is in the right type (".CivBeyondSwordWBSave"), duplicate it, rename it to the desired map title, and take your "Europe large.txt" file, go to file, click save as, underneath the highlighted file name, change the "Save as type" to "All Files", and then double click the file you have duplicated. This should change the .txt file to a .CivBeyondSwordWBSave file.
I went ahead and did this myself and attempted to load up the scenario. I was able to select my civilization and click start game, and it crashed. Presumably due to the file corruption that you can see in this screenshot I took of the file:
View attachment 488601
Here is a comparison screenshot taken of the beginning of a file for one of my maps:
View attachment 488602
As you can see, there are a whole lot of places in your file where you will need to press the enter key to correctly space out the lines.... If you know how to make a python script you could probably run a program that presses enter before every tab/indent. I don't know how to do that, and I wouldn't want to do it manually either. Better idea to just find a working version of the file and copy/paste that first section (from "Version=X" to just before "BeginMap"). Let me know how it goes.
