There are many of different reasons why this error can occur, and in my case, it was a reason that no one else has written about (that I could find), so I figured I’d post up the cause of my problem (and the solution).

This application was on a shared development server with a few other applications. They all used the same mySQL server. One of my other applications had a corruption in a few of its tables, and whenever this application was called, it would crash the mySQL server, triggering a “Mysql::Error: Lost connection” for all my other applications connected to the mySQL server at that same time.

I tracked down this issue by check the mysql logs, and then I simply reloaded last nights backup of the corrupt database, and everything was fine! It just goes to show you how important it is to always perform regular backups of your databases.

I hope this helps someone!