-24949: ERR_USREXISTS - user entry already exists 

Explanation:

This DBM command cannot be used, as the user name already exists.

User Action:

Use a name that has not already been used for a user, or delete the existing user. Only delete a user if you the user is no longer required. When you delete a user, you delete all of the saved settings for that user. To delete a user, use the DBM command user_delete.