[TYPO3] News categories tree not availabe in Relations after move?

[Bing Du]

Hi,

I set up a new typo3 4.0.2 and installed tt_news 2.4.0.  We are also 
running another typo3 server which is 3.8.1 and tt_news 2.2.24.  I 
exported the part of the page tree that has all the news categories and 
news items from the 3.8.2 server to a .t3d file and imported to the 
4.0.2 server.  Web->List shows the news items and categories fine. 
However, when I get into any news item, if I click Relations, the 
categories tree is empty.  It just shows 'News category' with a globe 
icon next to it.  Nothing else.  And at the top, it has a bright yellow 
message box saying

  RECURSIVE CATEGORIES DETECTED!!
  This record has the following recursive categories assigned:
  CoE%20In%20The%20News (21)
  Recursive categories will not be shown in the category tree and will
  therefore not be selectable. To solve this problem mark these categories
  in the left select field, click on "edit category" and clear the field
  "parent category" of the recursive category.

I clear the field "parent category" as the message suggests to no avail.

Any ideas why the problem and how should I get the categories connected 
  back into a hierarchical structure again?

Thanks in advance,


Bing