is your box running as a DC?
Xtraction is not supported on a DC.
@Andrew - is it that Xtraction isn't SUPPORTED on a DC or that Xtraction WON'T WORK on a DC? The former won't explain the cause of the original problem. I am not aware of any technical issues preventing Xtraction from working when installed on a DC, though I can completely understand not wanting to support such a configuration. Also, I don't see anything stated in the Installation Guide and Installation Requirements document indicating the DC restriction.
@Shane - have you confirmed that all of the Web Server (IIS) role features are installed based on the listing included in the Installation Guide and Installation Requirements document? The 404.3 error indicates you might be missing the ASP.NET-related features.
Edit - I just noticed that the original post was from 2 months ago, so I HOPE Shane resolved the problem long before now. If not, I'm sorry that it took so long for a response.
Yeahp Xtraction on a DC is not supported but should still work.
I have just installed Xtraction on a basic IIS server and I receive the same error as Shane reported.
So as GreggSmith mentions check you have all the required role features installed on your box.