taxonomy migration

Hi everybody. I ran into a problem when exporting users and taxanomy data to another drupal installation.

Basically I was getting an duplicate Id error when I was trying to add a taxonomy term to a vocabulary.
I know that drupal is not using auto_increment. The core taxonomy module is not using db_next_id() function, why is that?

Do I have to change the sequence table everytime i migrate something to a new drupal installation?

-dan