GeckoPie

http://www.ryanvm.net/forum/viewtopic.php?t=5657&start=0 Look at the second method, that can intergrate .NET Frameworks 1.1, 2 SP1, 3 SP1 and 3.5. I recommend using nLite and add the file you download above under "addons" within nLite. Or you could use the RyanVM Intergrator.

You were told to do it under [unattended] NOT [GuiUnattended] like you have. Hence it isn't working, read instructions.