Master Levels won't save?!

I am playing Master Levels (just smashed the Icon of Sin!) that are bundled with Doom II when you buy it from GoG. Saved Map 1 Attack with the usual Doom II menu and walked away from the game for a while. When I came back and tried to load this save I can find no place to do so in the usual interface for ML and when I try in Doom II the game crashes and quits. The GoG bundle of D2/ML runs on DOSBox. What can I do?