SQL Injections

Has any-one seen this before? What is the best way to prevent this again?

mysite.com 0 _HOS_EXTENDED_ 42.119.79.102 – – [22/Nov/2013:04:47:37 +0200] “POST /wp-includes/SimplePie/Content/Type/dc.php HTTP/1.1” 200 7359 “http://www.rabie.co.za/wp-includes/SimplePie/Content/Type/dc.php” “Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36” 5852 7642

Thanks