For the following reasons we have opted to no longer offer a Window x64 specific version of Crucible:
1. Crucible will never require more than 4GB of ram.
2. Windows x64 systems run 32 bit (x86) processes fine without any optimization.
3. The issue appears to be related to compiling and not the internal/development structure of the game itself.
4. We are currently focused on our next project.
X64 users should just download the X86 (32bit) file already provided.