MySQL Upgrade and Compressed Tables

Recently one of our MySQL servers crashed.  Luckily there wasn't any damage but after a support call it was found it was due to a bug with the version we are running.  We decided to upgrade to the latest version of 5.5.  We have one physical server running 10 small to medium MySQL instances (no replications).  Whereas 9 of the upgrades went as planned one didn't (there is always one!).