[support] duplicating Database problem

Using Drupal 7.12 I'm building a live site and wish to duplicate the database. I used phpmyadmin to copy the database on the server and cpanel to download to my pc.

I keep running into an error: ERROR 1062 (23000) at line 27: Duplicate entry 'comment_publish_action' for key 'PRIMARY'

I have tried mysql -uname -pword database < copied_data.sql copied the structure, have copied the structure only then tried to insert the data but get the same error. I tried deleting the offending INSERT INTO table but the error simply transfers to the next INSERT. Haven't run into this before! Where should I look for help please. Thanks Roger