Do other games work fine with your DOSBox 0.70, is this the only one? Because since DB makes the games run in the same virtual environment independently of the real computer you run DB in, this is really strange. It would make more sense that your DB installation wasn't right and other games didn't work either.
EDIT: Better just ask in the DB forums, you'll get specialist help:
http://vogons.zetafleet.com/index.php?c=7