Vista - Cannot delete empty imported folders

I imported Oldmail from OE6 with the method described in
www.oehelp.com/backup.aspx#oe2wm .
I experienced that when you try to import many folders at one time, some of
the folders caused errors and resulted in 0 imported messages. Therefore I
proceeded with importing the folders one at the time and this method did not
cause the import errors.
The result of this way of working is that I have now a long list of Imported
Folder,
Imported Folder(1), Imported Folder(2), etc.
After moving the old message folders from Imported Folder to Local Folders
the Imported Folders are empty.
My problem is now that I cannot delete the long list of empty Imported Folders