I got this sending to both firstname.lastname@example.org and 32665. The referenced page is no help at all, and my phone number is registered with Facebook Mobile.
"You have uploaded from an unrecognized address. For instructions on how to upload photos to Facebook, go to http://www.facebook.com/mobile"
It turns out that there's a new secret email address. On the Facebook site click the icon to share a photo:
Then click Upload a Photo:
Then click upload via email:
Your personal email address is finally revealed and can be used to send a photo via MMS.
Facebook - update your error message to point this out!