Hello,

well this is not an upgrade, this is a weird operation mixing data from different databases. Still not sure what you are attempting to do with this. I've not idea about the issue, because that could be related to different version of MySQL database, server etc

I suggest to run again the JChat 2.10 installation on the development server after that you tried to import tables from the production server. At least this will ensure that the installer script to align database structure to 2.10 run again after the import.

Best regards
John