Maybe it's just us, but we've been asked whether our Facebook photos and galleries were loading in the official app. Sure enough, we can see the galleries but when we click on an image, we get the above error message, which is quite interesting (and annoying).
Photos seem to load in our Mango Picture Hub, but some are having problems there too. The issue seems to be hit or miss with some users reporting to us no problems at all while quite a few others are getting the "Unable to load this page" message.
If it's the latter case, then it seems something on Facebook's end and not the app itself, presumably meaning no "fix" is needed for our app. We'll keep an eye on this one... Report in comments on your situation. (Thanks, Amir and our Twitter followers!)
[Oh and yes, notifications are wonky. All we can say on the matter is they work better in Mango than NoDO.]