The GOG version of Dark Forces includes a "CD.ID" file which is used to pass the CD check. Apparently, it needs to be in the root directory of the CD drive specified in DOS. I don't know how Magic Dosbox works in this case, but this might help you: https://www.vogons.org/viewtopic.php?t=20032
Otherwise, you can use Dark Forces DeHacker and use its included No-CD hack. Download link at the bottom of this page: http://ctpax-cheater.losthost.org/htmldocs/trouble.htm#df
The DFORCEDH.EXE included there is a DOS program, so it should be possible to start it with Magic Dosbox, activate the No-CD hack and any other option you would like to set, and then run Dark Forces.
Thabks for the info, i will check it out, i bought most of my DOS games just to play on my tablet