Rather than just deleting stuff, have a look at the installation log for the patch you're trying to apply - this should explain why the installation is failing. It can be found in C:\WINNT\KBxxxxxx.log. Also have a look at the WindowsUpdate.log file to see if that offers anything useful not in the individual.
Otherwise, as mattross says, try deleting the SoftwareDistribution directory and trying the install again. Have had to resort to this on a couple of occasions myself. The "wuauclt /resetauthorization /detectnow" command is for when you're talking to a WSUS server, so you could just as well visit windowsupdate.com if this is on your home PC.