When worldbuilder is starting up, it checks the code. If there isn't any problem, it starts up normally. If it finds a problem, it gives you an error popup, and says where it found the error.
If worldbuilder doesn't find anything wrong, but the game is crashing, you'll have to go and undo your changes one by one until it starts working again [process of elimination]. Once the game works again, you found your problem.
Also, if your using finalBIG, when you right click and click Go To, it should have a list of all the objects in that file, then if you hover over one it should show a list of that unit's modules, etc. If it doesn't show some of the units past a certain point, and starts showing modules in the list where all the objects are, then there is an extra END statement or an END missing somewhere.
Note that if worldbuilder finds somthing, it will say what file it's in and give you a line number. To find the line, use notepad [or Edit with Editor, if using finalBIG] and us the GOTO option. when you click GOTO, it will open a small window where you can put the line number, and it will take you there.
