I just installed SOS to check this one out for you, been a while since I messed with it. This game loads a sound driver called PMDIBM.COM to product FM synthesis sound. That message you see means the program tried to run, failed, and quit, after quitting the batch file unloads the sound driver.
My guess as to what is going on: You may not know it, but there is a form of copy protection for the game. There is a file called 'cdata.000' that must be available to the game. If you have the CD, mounting it should work, (but I can't say anything about this, as I don't own the CD, or disks for this game).
If you downloaded your copy and have no CD for the game, the cdata.000 file must be in your Temp folder, AND, the temp folder must be in the path for DOSBOX. (Confusing, but don't confuse this with your Windows temp folder, you must have this available on the C drive you mount in DOS-BOX).
What I would do is: Make a folder on your hard disk called Cdrive (or whatever you like). Put your SOS folder into that folder. Now, make a new folder in the Cdrive folder, called Temp. Look inside the archive you downloaded of SOS, and you should find a file called CDATA.000, (it may be zipped up in a seperate file, it was for my copy). When you find the CDATA.000 file, copy it into the temp folder you just made above.
Once the file is in place, mount the Cdrive folder you just made in DOS-BOX as your C drive, and type the following:
set path=c:\temp
Now you can go start the game bye typing SAKU-FM, it should run fine.
Hope I haven't confused you too much. ^^;
Idaho