Hello, I got this error: PHP Fatal error: Call to undefined method Zenphoto_Authority::getMasterUser() in /home2/centerv7/public_html/photos/zp-core/functions.php on line 1972. Not sure what to do now. It happened over the weekend and no one was doing anything to the backend of the database. Any advice?

Please see your server error log. Please also see the guide about error reporting:
http://www.zenphoto.org/news/general-contributor-guidelines#reporting-bugs

I got the error from the server log. We are running Zenphoto 1.4.5.9 with the zp_skeleton theme. Using Google Chrome browser. Not sure how to see the server configuration on the backend or to see which plugins are active (I know we use the metadata one). Here's the full line of the first server error, which keeps repeating: [01-Mar-2014 14:14:07 America/New_York] PHP Fatal error: Call to undefined method Zenphoto_Authority::getMasterUser() in /home2/centerv7/public_html/photos/zp-core/functions.php on line 1972.

Try an official theme please. zpSkeleton is actually not compatible with 1.4.5 unless you use the roughly updated one I made once (you find them on our unsupported repository on github). The developer has abandoned this theme.

Can you suggest a good theme that supports mobile viewing? That's the reason we picked zpSkeleton. I am reinstalling the release, so we'll see if that fixes the server error and I will then take your advice on the theme.

Thank you!

Reinstallation fixed the problem. I will now work on the theme.

The successor of all themes by gjr who did the zpSkeleton theme is the zpBase theme. That is also responsive.

Of the official themes only the jquerymobile theme is mobile capable. Official themes are scheduled to be reworked and then will be responsive as well. If there weren't those time issues…