Your patch.inf is corrupted so it's trying to download the very first patch file available, and all patches after that. Sometimes (for reasons we've never understood), it blanks the patch.inf instead of saving the number of the patch it's installed.
There is no way to prevent it from happening (well, there probably is, but we have no idea what it is!), but when it happens, immediately cancel (before it finishes the 2011-4-4 patch), and do the following.
IF YOU HAVE LET IT APPLY SOME OF THE PATCHES BUT NOT ALL BEFORE CANCELING IT, YOU MUST REINSTALL OR WAIT OUT THE PATCH PROCESS COMPLETELY BEFORE CONTINUING - If you wait out the patch process completely, patch.inf should be updated correctly and there is nothing more to do (until this happens again).
Open patch2.txt, find the number next to the last patch YOU ARE ABSOLUTELY SURE IT DOWNLOADED AND APPLIED. A patch dated from before the last time the game successfully patches would be what you're looking for.
Then enter that number here - http://choobs.org/stuff/patch.php
Download the patch.inf it creates and put it into your RO folder, in place of the patch.inf that's there.