I find you are far better of making your own discs or getting them from someone you trust to make them right. Pressed discs, like those in books and magazines tend to be OK, but often out of date. Discs that you buy on the Internet, particulaly from the electronic bay of theives, tend to be bad news.

If you have not burnt ISO files before, I suggest reading the entire downloading faq referenced in answer #1. Lots of people ruin their first few discs because they don't know a few basic things it covers. I'll be interested in hearing if you can make your own 5.1.1 disc and if it boots properly on that same 433 system.