As far as I know, you should use Earthworm James Rom Pack. But I have uploaded my own romset and ran into the same problem. To generate the list with the script you have to modify it a little.
Open create_rom_lists.py and insert a new line at position 911 before "pDialog.update(..." :
N64_Rom_Name = Rom_Name_noext
Now at least the script runs thru and generates the gamelist with your romnames from the filenames.
create_rom_lists.py