Several errors after installing plugin

Hello,

I just installed your plugin for the first time and I’m getting these errors:

https://www.dropbox.com/s/4pd27vm62quh5yn/Screenshot%202016-02-13%2009.18.42.png?dl=0

I’ve removed the plugin, but I’d like to use it at http://www.surfcityapps.com. This is a multisite installation, in case that makes a difference.

I’m also eagerly awaiting your App Card feature. 🙂

Cheers
CJ

https://wordpress.org/plugins/jm-twitter-cards/