Glad to hear that the map exported, but however,
the reason the objects do not work is because they must have their own object group. The ones that came with FH cannot be used. ex: Miscellaneous, MyRocks, MyTrees, etc, etc.
There is an easy way to fix this without having to remake the map as well.
Go into object maker and load all the objects used in the map individually, saving them to a new Object group. Usually, I just make the name of the group the same name as the map. Once they have all been saved into the new object group,
go to C:\FeralHeart\media\terrains
and then go into that map's folder. You'll see a .cfg that says
{MAPNAME}Objects.cfg
Open it in notepad.
Press Ctrl+H or go to Edit->Replace...
and type in the name of the old object groups one by one in the Find what: section, whichever ones you used ex Miscellaneous, MyRocks, MyTrees, etc, etc, and in the Replace what: section, you need to put the new object group's name.
So really we're just replacing all the old names with the new name of your new object group.
...Let me know if this isn't making any sense. xD