Mysqli_fetch_array() expects parameter 1 to be mysqli_result, bool given in

I'm have some trouble checking if a Facebook User_id already exists in my database [if it doesn't it should then accept the user as a new one and else just load the canvas application]. I ran it on my hosting server and there was no problem, but on my localhost it gives me the following error:

mysqli_fetch_array[] expects parameter 1 to be mysqli_result, boolean given in

Here's my code: