cclu

When I download and activate the plugin, I get the orange error notifications that say

“Notice: Undefined index: which in /vagrant/wordpress/wp-content/plugins/awesome-filterable-portfolio/afp.php on line 814”.

They point to lines 814, 833, 856, 864, and 874. This blotches out my entire sidebar so I have to deactivate the plugin in order to navigate my dashboard.

Another error is stated above my list of plugins that says,

“The plugin generated 8505 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.”

I’ve tried switching to the twentyfifteen theme, but I still get the errors, and I’ve tried installing the plugin on two different unrelated computers on two unrelated local staging sites with different themes. I’ve also tried removing all of my other plugins in case there was a conflict, but to no avail.

I don’t suppose this is a browser problem? In both cases I’ve used firefox. That aside, I’m at a loss as to what’s causing these errors.