you dont say what os you are using but i am guessing you are using nt or 2000 or xp as sunmap dll errors tend to be on nt kernal systems.t if you are going to be playing more than one old school direct x game, maybe a duel boot system, with 98 on your c drive and xp on your d. its not to complex to set up and its easy to find loads of tutorials on how to do it, there is probably one on this forum.
if you want to try and get it working on your pc though without having to reinstall o.s then try these guys
here