when I login to groups.drupal.org - I get Account Uniqueness Problem detected message.

This is the user on groups.drupal.org with your username:

http://groups.drupal.org/user/40500

That user has a different email address. So we need to confirm those are both your accounts and then set both accounts to the same email. You've already confirmed you control your drupal.org account by posting here. I sent an email to the groups.drupal.org account and replying to that email will confirm that's also your email. The last step is to decide which email you want to use.

I set your groups.drupal.org account to use the same email address as your drupal.org account, which should allow your accounts to sync so you can login without problem. Please confirm it's working for you now.