Do you have any objects inlcuded in the map that you installed to the game? Also, have you made any changes to your objects as well? (Such as adding an installed object to a default object group). What is the map's name exactly? I'd like to hear more details about this issue. Maybe you could save your map and relaunch the game and try exporting again? As well as maybe reversing any changes you made before trying to export if that other option doesn't seem to work out. You could also check in the Local Disk (C:) \\ FeralHeart \\ Exports folder to see if it has exported at all beforehand.
Yes, I have a few object groups within the map, one of those was the one I deleted. And no, I haven't made any changes to any default feral heart object group. The map's name is "Tanisawa~summer~" and I'll try checking my exports folder.