Hi N.A.Malik,
In your unattend file, you used 32 bit (x86) components:
<component name="Microsoft-Windows-Setup" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" processorArchitecture="x86">
However, the image that you used to create the unattend file is 64 bit (x64):
wim:d:/data/win8-fjs-oem-x64/sources/install.wim#Windows 8
However, in this case it's the architecture of the boot image that matters. If the boot image you are PXE booting to is a 64 bit image, you need to change the components to the x64 versions.
More information about this can be found in the TechNet article 'Best Practices for Authoring Answer Files'.
Hope this helps,
David
Windows Outreach Team - IT Pro
The Springboard Series on TechNet