For me the convert.bat is broken due a missing directory change before calling the Python script. Windows cannot find the script due current working directory for a drag&drop operation is always the source directory of the dragged file.
Viewing post in Midi2Dmf Deflemask Midi Converter comments
I commented the the first line of the batch to show the error: 9:32:44,74 C:\projekte\sega development\midinotes > python midi2dmf.py -v "C:\projekte\sega development\midinotes\OVER.MID" "C:\projekte\sega development\midinotes\OVER.dmf"
python: can't open file 'C:\\projekte\\sega development\\midinotes\\midi2dmf.py': [Errno 2] No such file or directory
The call is not executed in the correct directory. This isn't an issue of the python installation, it is wrong assumption what is the current working directory.