Thank you for letting us know and sorry for the inconvience.
The problem is caused by the way we had called a function on that line not being supported by php earlier than 5.3. This was my mistake as the plugin is intended to work on older versions of PHP and I will have a fixed version up shortly.
In the meantime we will need to remove/deactivate the plugin from your site. The easiest way is using FTP access to delete the /kebo-twitter-feed/ folder from your /public_html/wp-content/plugins/ folder.
If you do not have FTP / file manager access let me know and I will see about resolving this another way.