I have only had this issue when someone enters an account into the joomla User Manager directly and doesn't start the process in CB, the error happens when the databases try to sync. The CB database does not play well when it has to pull data and lacks the fields.

Go to Menu Manager [ usermenu ] then select unpublish [Your Details]. Your member will no longer be able to change their account information.

In your Admin Panel go to Global Configuration then click on the Content Tab, the second to last option is Back Button... make sure <SHOW> is selected. If it is already check your error log.

create the chat folder on the server. Then re-upload all of the folders a few at a time, and the large ones by themselfs. The try to configure, I'll bet it will work. Some FTP programs don't upload all of the data or it gets messed up. Make sure you select the Joomla csm from the list. This will integrate it into your member datebase, this is nice because your member will not need to login a second time. Also make sure your "chat folder" is installed under your root dir.

I'll check back one your post latter tonight.

Good luck, when you get this working I am sure you will feel like this was the best 5.00 you ever spent.

Colin