It appears that Sun Microsystems made a change to their website that breaks the legacy patching solution which is based on PCA.
Basically, Sun added a screen that forces the user to sign off on a license agreement prior to downloading the file(!) As if this wasn't bad enough, the agreement isn't cached. So it's not like you can agree to the license once, then continue on your merry way; you have to click through it each and every time you download it.
Here's the URL for the file:
Here's a thread on Sun's forum describing the problem:
The short term solution is simple - download the xref file manually, host it on your own http server, then point SPC to the new URL.