DB Tables: in use

About an hour ago some of the tables in my DB have "disappeared" and cannot be accessed. When I check with phpMyAdmin, I see some tables fine and some are marked 'In use' and cannot be accessed. What's happening?

See here:

Update:
It looks like all of my tables were converted from InnoDB to MyISAM? When I try accessing some of the 'In use' tables, I get: #1286 - Unknown table engine 'InnoDB'

Update:
From what I could figure out by now: INNODB support on my site was turned off all of a sudden, rendering all my tables suddenly corrupt. I cannot restore from backup (cause all the backup is InnoDB) and I cannot recover. This was done without notice or warning on a Friday night without any support expected for several days. What the hell? This is an extremely unprofessional move, Altervista. What kind of a business are you guys running? Even in the unlikely case I would be able to recover my lost DB tables from backup - data has been lost.

[karl94]

We checked your tables and found no issue with them, InnoDB support hasn't been deactivated.

There was no change in my tables cause I spent the weekend recovering from backup and filling in the lost data.
Tables were all switched from InnoDB to MyISam. Why?

[Gianluca]

evetools:

there is no reason we should have turned off innodb for your database, no manual operation was performed on it.
Phpmyadmin may have shown a wrong engine when these tables were marked as "in use", this happened because you may have hit a mysql bug and while this issue is under investigation your website has been temporarily moved to another server