1.04 is not needed to solve this problem
#1: Go to your jk2mp.exe
#2: Right click it and then click "properties" at the bottom
#3: Click the "Compatibility" tab
#4 Check the box that says "Run this program in Compatibility mode" and select Windows 98 from the dropdown box.
#5: Click "Apply" and "Ok" and then try running JK2MP again and see if it works.