1. Duplicate Entry Error, 2. Permission Errors, (Migration/Database)

Problem 1:
When I try to post a new page I get an error simmilar to the one below (the autoincrement value on the nodes table is correct), could you tell me were the increment value is stored because it seems to me that the nodes table is the wrong place.

user error: Duplicate entry '10' for key 1
query: INSERT INTO harrypotter.node (status, moderate, promote, sticky, comment, title, body, format, uid, created, type, teaser, changed, nid) VALUES('1', '0', '0', '0', '0', 'Privacy Policy', '

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1. Collection of Data.
Our registration process requires only a valid e-mail address and a unique user ID and password. Providing us with other information is at your option. Please take note that your user name, e-mail address, or other submissio in /home/wizards/includes/database.mysql.inc on line 66.

user error: Duplicate entry '10' for key 1
query: INSERT INTO harrypotter.node_comment_statistics (nid, last_comment_timestamp, last_comment_name, last_comment_uid, comment_count) VALUES (10, 1127925720, NULL, 2, 0) in /home/wizards/includes/database.mysql.inc on line 66.

warning: Cannot modify header information - headers already sent by (output started at /home/wizards/includes/common.inc:384) in /home/wizards/includes/common.inc on line 192.

Problem 2:
I imported all my users from postnuke, but now all of them don't have the authenticated user role enabled. Which table is this role stored in so that I can write a script that makes everyone authenticated?