.54 works fine for me also.
Perhaps the upgrade file got corrupt during the download. I had a lot of trouble downloading the upgrade. The site was unresponsive the first few days, and when I finally got through, my first dl attempt froze about half way. (Could have been a problem with my ISP though. - Wouldn't be the first time!)
Here's some info on the file:
Name: nero551054.exe, Size: 13,671,289 bytes, CRC-32: 2F5B9A98
If your numbers differ, you might want to try again.