Hi all -
As LabVIEW FPGA is only a 32-bit application, it requires a 32-bit LabVIEW Development System as well, as T-REX$ said.
More information can be found in the readme, here's the one applicable for LabVIEW 2012: KnowledgeBase 5XTFRQFM: Where Can I Find the LabVIEW 2012 FPGA Module Readme?
Hope that helps!