This is PC Booter game. I don't remember exactly, but I think you need to change config of Dosbox to boot from this disk image instead of running normal DOS.
I remember playing
Mouser which is also booter but for PCjr machine. So, if you run normal DOS, try the same thing without changing config file: go to directory where Ghostbuster file is and type "Boot gbusters.img". See if that helps.