Error User.save

Issue Summary

Using the user.save method I receive the following error:

user warning: Duplicate entry '' for key 2 query: INSERT INTO users (created, access) VALUES (1254426886, 1254426886) in htdocs/modules/user/user.module on line 327.

I'm using Drupal 6.14 and the lastest version of AMFPHP and the Services module.

I've done several searches through the forums, and tried executing several of the suggested fixes, but no success yet. (I already have a user established with an ID of 0, and it is already set to "auto-increment" as some of the existing postings have suggested. I've tried a fresh-install, too. Still no luck.)

One clue here is that the duplicate entry is actually listed as empty ( '' ) which is a little puzzling but might be a clue.

Please help - I'm relatively new to Drupal and if I can get past this issue, I feel like I'll be on my way to building out my project.