no such file or directory in class-feed.php

Several of my sites are showing the following at the top of the home page, and several are not. This is several weeks old, What is happening?

Warning: file_get_contents(http:) [function.file-get-contents]: failed to open stream: No such file or directory in /home/myhostloginname/mywebsiteurl/wp-includes/class-feed.php on line 88