Go into your exports folder in your FeralHeart folder and delete the [yourmapname].fhm, [yourmapname].fhs, [yourmapname].fho, [yourmapname].fhw from the exports folder. After once you've done that, go back into FH and export your map again. Make sure that ALL the objects in your map have been exported. If they haven't it will tell you on the screen.