At what point in the instructions does the phone freeze, it would be something I think we would like to test and see what the issue could be. If you could also let us know which model of the iPhone you have (3g, 3gs, 4) and what version of iOS it is by using Settings -> General -> About and look for the version number e.g. 4.0.1.
We have tested the instructions on different iPhones before without an issue, but it is possible there is a bug in a certain model and/or iOS version combination causing an issue with the instructions.
The only general issue I've seen with following the instructions is sometimes people will choose Other or IMAP/POP account as the email type instead of Microsoft Exchange during the setup process. If this is done, the settings will not work properly and cause issues.
Hardware Support Specialist