I set up a new installation of K2 on a new Joomla project website. I created a user for each type of user group in Joomla and then I imported them through the K2 User Manager, so all of the user groups would be created in K2. Then I registered a new user through the frontend, which created the new user as a "registered" member. The email was inaccurate though and there didn't appear to be a way to resend to the correct email. So I went to the K2 User Manager and changed the K2 "registered" member that I created to a "Super User" manually and published it . Then I realized the Joomla also had the member as "registered," so I changed it to "Super User" for that newly created member also. This error message came up and now I can not access the K2 User in the Manager section.
This is the error message that is showing, "The ne1054 Unknown column 'juser.usertype' in 'order clause' SQL=SELECT juser.*, k2user.group, k2group.name as groupname FROM tyg0j_users as juser LEFT JOIN tyg0j_k2_users as k2user ON juser.id=k2user.userID LEFT JOIN tyg0j_k2_user_groups as k2group ON k2user.group=k2group.id LEFT JOIN tyg0j_user_usergroup_map as `map` ON juser.id=map.user_id WHERE juser.id>0 GROUP BY juser.id ORDER BY juser.usertype asc LIMIT 0, 20 ..."

Do you know how I can repair this?

K2 User groups do not replace the ones from Joomla!.

Joomla! user groups are still required for backend access. K2's users are for front-end editing credentials.

In my opinion you should start over. Please uninstall K2 and reinstall it if you haven't entered any content.

Krikor, thanks for your input. While I was waiting to see if anyone knew what I needed to do I decided to do a few things myself. I deleted the newly created "User" from the Joomla Users & was still unable to access K2 Users under the Components menu in the backend. I created a User with the same information as an "Administrator" and as a "Super User." When I went back to the K2 Users option under Components, I was able to access it at that time. Anyway, it seems to be working fine now. Do you think that I should still uninstall and reinstall? I don't want to continually be trying to find a fix for odd issues, but this one appears to be fixed up.

It is quite possible that there was never an issue.
Your new user never had the credentials to access K2 in the backend.

In my opinion it is best to use the default Joomla! user groups and only create a new one if it is needed.
As for K2 user groups you need them if you want to enable front-end editing and you have multiple authors with different posting credentials.