A few months ago I had an Exchange Server 2007 install stop cold, caughing up this error:
Service 'MSExchangeTransport' failed to reach status 'Running' on this server.
Apparently if you disable IPv6 on a Windows Server 2008 the error will occur. Not to be picky, but how many networks are actually using IPv6 and why is it installed by default anyway?
So re-enable it, reboot and try the install again.