How do you load this up in Zandronum? I get:
Script error, "DOOM_Complete.pk3:menudef.txt" line 1: Unknown keyword 'AddOptionMenu'
Open up the PK3 in any program that can edit ZIP files and delete the file menudef.txt contained therein, that should allow Zandronum to load it.
I created a bug report for Zandronum for this years ago and I guess it's still not fixed: https://zandronum.com/tracker/view.php?id=3205