The error is coming from the mysql data client (MySql.Data.MySqlClient.CharSetMap.GetChararcterSet). A quick search for "mysqlclient.charsetmap key was not present" turned up a few results suggesting that the data client in the application (mojo) is too old for the version of mysql you're connecting to or that the character set specified on the database isn't supported by the data client in the application (mojo).
So, a couple of questions:
- What version of mojoPortal are you running?
If you haven't upgraded in a long time but are running a new version of MySql, you need to upgrade mojoPortal.
- What version of MySql are you running?
If you have upgraded this recently, and you haven't upgraded mojoPortal in a while, you need to upgrade mojoPortal.
- What is the character set specified on the mojoportal database?