Needed a plugin that just lets me add a Facebook and Twitter button to share this website. Found Share Buttons by E-MAILiT.
Installed this plugin on a brand spanking new WP 3.8.1 install and immediately got the following error:
Notice: Use of undefined constant plugin_type - assumed 'plugin_type' in /wp-content/plugins/e-mailit/emailit_widget.php on line 183, 184, 186
An undefined constant shouldn't be too hard to fix :-)