The OS was built and running fine on my SHuTTLE SH67 32GB, i7 CPU Vmware 5.1.0 box.
The moment i tried to copy a ISO (smaller files seemed to be ok) to or from the Windows 8.1 machine the entire ESXi box would PSOD.
Connecting from the *.1 to a XenServer machien to install the client tools also rendered the ESX PSOD.
Change the Windows 8.1 from using the E1000 network NIC driver to the VMXNet3. All problems gone! (for now!)
Assuming here that your ESXi environment is already nested and configured appropriately.
Power Off the guest ooerating system you want to enable FT for
Disconnect the CD / DVD (or select client devic eoption)
GO to options tab and sele the Advanced / General Button
ON right hand side click configuration parameters button
Add 3 ROWs
Name: replay.allowFT Value: true
Name: replay.supported Value: true
Name: replay.allowBTOnly Value: true
You ned VT-X as a feature of you rphysical CPU adn this needs to be passed through to your Nested ESXI host.
http://www.virtuallyghetto.com/2012/08/how-to-enable-nested-esxi-other.html < See this blog for more details.
It matters greatly if you are using ESXi 5.0 or 5.1