from the version number I conclude that you are talking about ABCexplorer. You must write this full name so that we know what you are talking about.
The tool is quite useful, but has its limits and bugs. I have not managed to make it transpose either. If you can work with command lines,
C:\Programs\ABCexplorer\abc2abc d:\mymusic\myfile.abc -t -5 -b > d:\mymusic\myfile.abc
will do the job; replace -5 (meaning a fourth downwards) by the interval in semitones. I do not know if the programmer "Billig" is still active, maybe you want to switch to EasyABC, which isn't perfect either, but improving quickly.
( http://www.midicond.de/Freeware/index_e ... idiZyx2abc