The error is because 10.4 used an older version of python.
I tried a lot of workarounds but haven't got it to work natively.
However I did get it to work with Wine, so if you have Wine installed:
in the terminal type
Code:
wine cmd


then change directory to the unzipped windows version, type
Code:
cd Downloads\mjb2lite-win-dist


then with the .SGU or .mjb file in the same folder, type
Code:
mjb2lite.exe "my song.SGU"


it will the create the midi file my song.SGU.mid

if you don't get the Windows command prompt with
Code:
wine cmd

then in the terminal type
Code:
sudo ln -s /Applications/Wine\ Stable.app/Contents/Resources/wine/bin/wine /usr/local/bin/wine
sudo ln -s /Applications/Wine\ Stable.app/Contents/Resources/wine/bin/winecfg /usr/local/bin/winecfg
sudo ln -s /Applications/Wine\ Stable.app/Contents/Resources/wine/bin/msiexec /usr/local/bin/msiexec

If you installed 64-bit wine also:
Code:
sudo ln -s /Applications/Wine\ Stable.app/Contents/Resources/wine/bin/wine64 /usr/local/bin/wine64


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