Unfortunately, I don't have the hotfix but you can "fix" (no guarantee at all) your save by assigning the "api_scene_name" variable using the Renpy console (shift-o, use
unren.bat if not available) and then move to another location (hence, you mustn't be in a dialog situation).
The available "api_scene_name" strings are the file names of the .rpy files in "game\Rooms" 's subfolders. So depending where you're currently are in the save you can try to figure it out there.
In the console you gotta type in: $api_scene_name = "<scene_name>" (e.g. "monica_office_entry")