If I were to chime in with a random suggestion, most likely the database tables have been upgraded to 10.x (which is stable GA now btw) and the only way to recover them would be to have 10.x, then use innodb recovery parameter in my.cnf ( innodb_force_recovery = 1 - starting from the lowest until the SQL server starts, it's progressively more "forgiving" - read more at http://dev.mysql.com/doc/refman/5.5/...-recovery.html ), then mysqldump all the data, empty databases and re-import them.

However not knowing how badly the databases have been mangled in the process I'm left to guessing. I'd literally have to see it.