Same here. Trying to add new images to a gallery. It seems to go through all the motions but when I check for the images they are not there. Someone has screwed up big time.
Well I am already on PHP 5.2 (hosted) and YARPP 3.3.1, and when I make a change to a post from the admin pages I get the above error. The only way I can make a change and save it is to disable the plugin, make the change and save it, then enable the plugin again. I also have the same problem when working locally on a new site. Not really a good way to work – disappointed.