Duplicate entry '27' for key 1 query: INSERT INTO chatroom_msg_archive

I will look into this when I have time if no one else does. Until then, you can prevent the error by unchecking "Automatically archive old messages" in admin/settings/chatroom.

Just to confirm: I am getting the same error (also, displayed msg counter changes erratically). Thank you.
Duplicate entry '399' for key 1 query: INSERT INTO chatroom_msg_archive (cmid, ccid, uid, msg_type, msg, session_id, recipient, modified) SELECT * FROM chatroom_msg WHERE ccid = 7 AND cmid < 400 in /var/www/cms50/includes/database.mysql.inc nella riga 172.

Yes, I'm experiencing the same error as well:

user warning: Duplicate entry '1' for key 1 query: INSERT INTO chatroom_msg_archive (cmid, ccid, uid, msg_type, msg, session_id, recipient, modified) SELECT * FROM chatroom_msg WHERE ccid = 1 AND cmid < 422 in /var/www/drupal.meltonfoundation.org/includes/database.mysql.inc on line 172.

This could happen if two users enter the chat at the same time. Automatically archiving old messages is a feature for advanced users. At the moment, archiving is done whenever a user enters the chat. The logic was that it should work for sites that didn't have cron set up.

Maybe archiving should be a cron job. Any user advanced enough to use this feature should also be advanced enough to set up cron. What do you think?

Fixed in CVS commit 63778. Turned out to be a simple error in a variable name.