I am sure you have all heard this a million times but here's another for ya.

I have:
iPhone 3GS
iOS 4.1
BB 05.15.04

I am trying to run the update on OS X 10.5.8 PPC running the latest iTunes.

I have created the custom IPSW with the iPad baseband using PwnageTool, however when I try to use itunes to install it to my iphone it fails with error ranging from 1015 to 16xx errors, I would really like to know why this is acting this way?

Any help is appreciated.