You dont need to use export. If you click on the symbol beneath the board that has 2 dice, a folder and a dice cup, that will import your last match. To open any other (or if that doesnt work), then it is File/Open/Desktop(if that is where your javafibs lives)/Javafibs/matches/jellyfish/All files. When you save the match and the analysis, it will save it back into the same directory as an XG file.
Hope this helps.