Are you playing the disk version or the CD-ROM version? Sometimes I've had trouble off and on playing some CD games from DosBox like Laura Bow, Ecoquest and Willy Beamish. I think it's because I actually have a DVD-Rom, not a true CD-Rom, and it's getting confused somewhere. Copying all the files from the CD to your game directory on your hard drive solves that problem.
If you are using the disk version, did you INSTALL the game, or just copy the disks to your hard drive? Most of the "newer" Sierra games needed to be installed before they could be played. Try installing from the disks under DosBox.
Hope this helps, and it's not too "elementary"
-Tom.