I did a little research, and from my understanding, the game crashes whenever it tries to play an audio track from the CD. The image file on Abandonia here does have the data for the audio tracks, but as you said earlier, there isn’t a supporting .cue or .ccd file to designate those audio tracks.
There are two solutions that I have tried that have actually worked in preventing the game from crashing. The first solution is to use a no-cd patch for the game. Don’t know why it exactly works, but I tried it and it does. The second solution is to somehow recreate the audio tracks on the disk. I am attaching a .cue file to this post that will be able to create the missing audio tracks for this game. For some reason, you can not use the .cue file I’m providing to mount the image file in a virtual CD drive. Instead, you have to first burn a CD using the .cue file along with the .img file. Then, you have to make a image file of the cd you just burned. I use Imgburn to burn the disc and Alcohol 52% FE to create the image file of the disc. After that, you should be able to mount the new image file in Dosbox and play the game successfully. I hope this helps you and anyone else having trouble with this game.
Mercenaries.zip