php error log

Hello,
I’m getting an error on my site every once in a while that completely slows everything to a crawl (and usually times out when trying to save a post) when it happens:

[11-Apr-2013 10:24:22 America/Chicago] PHP Warning: require(ABSPATHWPINC/option.php) [function.require]: failed to open stream: No such file or directory in /mnt/stor3-wc2-dfw1/504110/762059/www.chicktime.com/web/content/wp-includes/functions.php on line 8

I ran the site through
http://sitecheck.sucuri.net/scanner/
http://www.unmaskparasites.com/
It came up empty for viruses. The host (who had no idea what the error was) also ran a virus scan and didn’t find anything. Anybody know what this could possibly be?

I’m running the latest version of wordpress (3.5.1) with these plugins:
Advanced Access Manager
BackupBuddy
Facebook Feed Grabber
NextGEN Gallery
Role Scoper
RoyalSlider
Show Menu Shortcode
Sub Pages widget
TinyMCE Advanced
TPG Get Posts
WP Super Cache

If you google the error, you see that plenty of other people have a similar error in their error logs, but I haven’t found any solutions. Any help would be much appreciated.
Thanks!