I cannot recall if I had this problem but basically you have to go to this topic on Unicornation.
http://www.motunation.com/forum/viewtopic.php?t=9411
Go through the five pages. Then find your way to the RME site which has a firewire fix instruction page. You get the Microsoft firewire fix (along the way) but that does not fix it.
Effectively you have to roll back the firewire drivers to Windows Service Pack 1 (about 2001). That is ok. It works fine on all systems.
Then you have to reset the SidSpeed (or add a SidSpeed) key in your registry from 100 to 400 bps.
Anything short of these steps and your firwire is throttled or kinked like a hose. Do not listen to those that say that speed does not matter.
I think what happened with your system is that it gets to the end and then tries to detect the firewire device but cannot because there is a fault in the firewire software interface. It was Windows that did this by 'fixing' firewire by throttling it back to 100.
I think there is another solution to this problem of getting near the instal and stopping. It was something like switching off and restarting it when it would go through but I cannot remember. Anyway this will still do no good until the firewire connection is fixed and back up to speed or that was my experience anyhow.