I tried to install and I am having this error: Fatal error: Call to undefined method WidgetFramework_Helper_String::splitPositionCodes() in /home/investireoggi/io_forum/library/WidgetFramework/Helper/Sort.php on line 13
If you tried to install the latest version 2.6.3 beta 12 (which I posted above) and got this error, then post your bug report in the bug tracker forum. The developer doesn't reply here.
@midego Find the widget at the List Widgets page in Admin CP. Edit it and look at the Position setting. Look for a name which you believe has to be the hook for the media gallery (I don't use/have the add-on, so I can't tell), and simply remove it. Save Widget.