[hamsterpower]

My guess is that this is a bookmarked link, and the bookmark was set in the "user profile", after setting daylight savings time (DST). The reason "profile.php" is not found, is you are looking in the base directory, "profile.php" was likely moved into the "forum" directory at some point. For awhile it has defaulted to the homepage when encountering this error, but now it only does on the third try for some reason.
I would reset the bookmark with a valid link in the most common location you visit. For me that is the "recent posts" page. Remove everything after the ".com" if you want the homepage. This does seem to be a user error not a processor error.
If that doesn't work, have you tried turning you computer off and then on again? A troubleshooting joke.