When you install you should first see the cromwell flash bios, which then allows you to put another bios onto the chip. You have never seen that, none of the lights on the chip are coming on and you are fragging. This means when the chip is enabled the xbox cannot find a bios.
From what you have said it seems clear that there is either something wrong with the install - its already been said but you need to look at all the soldering with a magnifying glass to check all the connections.
Or, something worng with the chip itself - not that likely.
btw - if you do not have the av connector in the xbox will always flash r/o, so keep it in!