When I got my external hard drive a couple months ago I also tried the Vista Backup Tool for the first time and luckily I did some testing with it because I noticed that my desktop couldn't access the backup created by my laptop (because of rights) and that if my laptop died it would be completely useless to me. As soon as I noticed this I formatted the drive again and just did a straight copy of my files so that no matter what I'll be able to access them from any computer.
It was pretty scary finding that out though and I definitely recommend people
not using it to do backups!
And sorry for your loss.