Facebook plugin - undefined function curl_get()

My prior Facebook plugin wasn't working, so I upgraded to the latest plugin. I also upgraded to the latest website membership at the same time. I followed the instructions for install the Facebook plugin, and made the necessary changes to website membership to point to the record where members are stored.

I've tried to login in with Facebook plugin several times, I checked the instructions many times, and my settings, but I keep getting the following error message when I try to login with Facebook.

Fatal error: Call to undefined function curl_get() in /home/domain/public_html/cmsb/plugins/facebookLogin/facebookLogin_utils.php on line 24

Anyone have any suggestions on how to fix?

Thanks, Zicky