I had the same issue. After downloading the script to test whether the plugin would work on my server or not, I came up with the error stating that…
allow_url_fopen is NOT enabled in php.ini
I’m guessing this is what was causing the error. Checked my hosting company and they have listed on their KB that they do not allow this by default. They recommend using a different, more secure method of doing this. This plugin looks useful, so I may try to re-write that portion without the fread, if possible.