XML import -term_hierarchy table - tid and parent fields same value.

I made a vocabulary and some terms in drupal.
After exporting and checking the xml file (wich was fine) I tried to import it again.(after resetting the drupal database and importing the mysql file)
Everything is ok except that the tid and parent fields (in terms_hierarchy) get the same value.
In fact the parent field gets the value from the tid field.
So there´s a faulty hierarchy wich means that drupal isn´t showing up any terms.

It´s also reflected in the INSERT statements that are visible after the import.
There you can see that same value is taken for the tid and parent field. (tid 1,2,3,4... parent 1,2,3,4)
As I already said, the exported xml file was correct. (showing the good parents)