Comment 4 for bug 800025

The only other thing is that the site was operating in German, the German langpack was installed. I can't see how that would have been a problem however.

I submit that you should just apply the fix anyway. That file mentions that function, therefore that file should have access to that function. require_once will prevent any problems, and there'll be plenty of other lower hanging performance fruit before you have to worry about an extra require_once.