Dunno if you squashed this yet, but using latest build int with vB, add a fave is fine... goto favorites and click remove to be presented with a white screen...
well, it works on your site, i looked for a missing lang string perhaps... i see yours says 'removed' i have > $Globals['pp_lang']['removed'] = "The image has been removed from your Favorites album!";
I would suggest yes if your link is that since in 5.62 since we use the AJAX that you try reuploading all core php files. Your using old files it would seem