This error showed up on my site as well, and it prevented any blog pages or photos from showing. All that came up was a blank page with a 500 error.
My host, TMD Hosting, took the info I sent them from this thread and did the repair mentioned above, which worked quickly. Thanks to those who posted this and found the fix - I appreciate it very much.
As Geek Girl says, it's a weird practice to allow a change by a third party like Facebook, to bring down all the Dolphin sites like this. I know Facebook compatibility is important, but this is pretty bad.
Thanks again,
Gary