Thanks, Where can I find it? and what is it for program?

I'm new to DOSBox and I kinda figured out how it works. However I have a problem with running EWJ2 (Earthworm Jim 2) I mounted D:\Games\EWJ2\ and I tried to run the EWJ2.EXE file in it, as I should. But when I press enter the following line comes up *No CDROM drives found. Make sure MSCDEX is …