When I take a german xdxf and convert it with the french files it does convert without problems. I think its a flaw of the source french xdxf file. So u have to search the net for more xdxf files until u get a correct one.
the french-english from here
work perfekt. In the same directory the french - french are user submitted and do not work. I am shure now its a source problem. Maybe we should open a thread with download sources for legal xdxf or dsl formattet dictionarys, which testet working