RFC822 specifies that a date string has an optional day: [ day "," ] date time Safari fails to parse the date if the day is not specified. "Wed, 24 Jan 2007 22:30:00 +0100" does work, "24 Jan 2007 22:30:00 +0100" should work but does not.
This is handled by closed source framework outside of WebKit. Please file a bug at <http://bugreport.apple.com> (free registration required) for Apple engineers to take a look. Closing as INVALID, since this is not a WebKit issue.