Why does RoboHelp 11 keep creating a folder when I import a topic?

I'm importing topics from RoboHelp 9 to RH 11. I have a folder holding all the main & sub-folders (let's call it MAIN Folder). Nearly every time I import a topic into one of the lower folders, I get a MAIN Folder along with it, which I cannot delete, so I rename it Extra Folder1 (on up to 6 so far). Why is this happening and what can I do to stop it?

Thanks.

LonR