Dear ChrisR,
I have updated my Win7PE_SE project today and I started to have problems building 64 bit PE builds. It seems that the problem is with the WoW64 Basic script updated version 11. It's trying to copy a files named "combase.dll" from SysWow64 folder, but this file doesn't exist there. I did a test and tried to find this "combase.dll" file in my Windows 7 ultimate 64 bit host system and it seems that this file doesn't exit there neither.
Are you sure that "combase.dll" file exist? My log is attached to this message (I've updated it).
Best regards,
Aeolis