As I said on the 'other' forum....Westnet.com.au are a really customer focused ISP. Don't forget to add the .au or else you are directed to an American ISP: westnet.com. Totally different.
I can stop looking now...I was almost close when I mentioned your router....almost.....
This is just a suggestion....I know this is frustrating the heck out of you but I am only able to think of one thing...power cycling your router (I'm presuming that you are using one). I will continue to search for any info on your very wierd issue.....
Another option is to download the itunes widget which captures the album art of the current track and gives you the option to set that album art either to one track or all tracks from that album.
Try this, go to Users/youraccount/Library/Caches and delete Safari.
Remove the Safari icon from your Dock if there.
Log out and log in, or restart
Another suggestion is to re-run Software Updater....
It's just that I happened to learn that today....pure coincidence you needed the same tip that I found....if you asked me yesterday I wouldn't have known.
I suggest maybe a rebuild of your iPhoto library?
Open iPhoto, click on help and in the iPhoto help search for Rebuilding iPhoto Library.
There are various methods for the different versions out.
Just open Safari and go to www.apple.com then when the page loads drag the icon to the left in the URL address bar to the right of the trash in the dock and that's it done.
You can do this with any website BTW.