MySQL 5.5 InnoDB = OFF?
Sounds like an issue with MySQL Workbench.

MySQL 5.5 has a default storage engine of InnoDB.

In fact, the option default_storage_engine is predefined as follows:


MySQL 5.5.4 and prior, MyISAM
MySQL 5.5.8 and after, InnoDB


There is another option called storage-engine, which was deprecated as for MySQL 5.5.3. Keep in mind that MySQL 5.5.8 was the very first GA release. 

I would strongly suspect MySQL Workbench if it is coded to check storage-engine instead of default-storage-engine. This would allow MySQL Workbench to monitor older release of MySQL.