What kind of vanilla limitation I broke here?

[Misty]

I wanted to test this map in chocolate doom to check all not working things, but it seems I exceeded some kind of limit which results instant crash with message. There is screenshot of this error and map for checking. I would like to know how to fix this map to be compatible with chocolate doom. Prboom+ and above runs that map without any visible problems.

EDIT:Problem solved and map removed from here. I had to rename flat lumps from FF_END to F_END. I wouldn't never guess it. 

 

 

Edited January 2, 2018 by Myst.Haruko

[scifista42]

Rename FF_END to F_END. (But keep FF_START as is.)

[Misty]

Wow, I wouldn't never guess it that wrong lump names cause so much headache. Thank you, it worked.