At http://members.cox.net/kplotkin/scanner.htm there are several programs for the PRO-64/2041 along with instructions. It would be worth grabbing all the files there and archiving them. Who knows, one of the programs there might be better than the ones you've been trying. Below is an excerpt from the wload64 help file to get you going.
1.) Plug 25-Pin or 9-Pin cable into the computer.
2.) Make sure scanner is off and keypad lock is off.
3.) Plug 3.5mm stereo plug into earphone jack.
4.) Press and hold down the “Enter” and “3” keys simultaneously and turn the scanner on.
5.) You should see “PC PGM” on the scanner display.
6.) Do not remove the stereo plug while the scanner is on!