When I set the Sound->MIDI->Device->Fluidsynth
I get this error in the DOSBox Status Window:
SYNTH: Failed to load MIDI sound font file "1"
MIDI:Can't open device:synth with config:1.
MIDI:win32 selected Microsoft GS Wavetable Synth
MIDI:Opened device:win32

There is a soundfont (1.sf2) in the root directory of the DOSBox SVN-Daum directory
I renamed the FluidR3_GM.sf2 soundfont to 1.sf2 but it does not work.