@alec, this is my plugins line form the config file:
$rcmail_config['plugins'] = array('plugin_manager','calendar','carddav','compose_in_taskbar','crawler','fancybox','folderbuttons','jscolor','lang_sel','persistent_login','placeholder','planner','plaxo_contacts','savepassword','timepicker','webmail_notifier','archivefolder','blockspamsending','zipdownload','message_highlight','database_attachments','contextmenu');
but i was also trying to run RoundCube without any plugin and still - same results.