Hello adn...
Go to "manager->tools->configuration->interface & features".
In the TinyMCE Settings section, make sure "custom" is selected as the theme.
This restored the editor styles menu for me.
However, you may find the styles don’t behave in the same way they used to...
see
http://tinymce.moxiecode.com/punbb/viewtopic.php?id=20905
G