The 64 bit Linux PE boot disk uses the 32 bit client via a comptable library and doesn't work correctly and has been causing issues that symantec has been advising people to just use the 32 bit PE boot disk.
Example:
https://www.symantec.com/connect/forums/linuxpe-always-kernel-panic
Called support and the solution is to use x86 regardless if the hardware is x64. Disabled x64 as an option on PXE and it's working fine.
So the question still stands that we need a 64bit versions of Ghost and Gdisk as linux is dropping 32 Bit support.
Thanks