You may have 2 unrelated problems, although I'm not sure why you require an Authorization Code. (VJ-1604's do not require any unless you want to bypass the ink cartridge smart card)
A) Your printer will not print because it is in an error condition (Undefined Media). It seems like the paper edge sensor on the printer is not working (not sensing the width of your media). You can try bypassing this sensor by going to the user setup menu and changing the media detection setting to "OFF" and see if the printer will go online (Ready to Print), if it does, you should now be able to print.
B) If you want to run the MSA program, you need to configure the MSA setup to match the printer's IP Address, then set a static IP Address on your computer close to this IP Address. I normally use the default setting on the printer's "Board Manager Mode" (192.168.001.253) then set the computer's IP Address to 192.168.001.250, also make sure Windows firewall on the computer is set to "OFF"