Welcome to the Community,
in order to run 64 bit guests you need to ensure your CPU (I assume it's an Intel CPU) supports VT-x and that "VT-x" as well as "Execute Disable" are "Enabled" in the system's BIOS. After changing any of the mentioned settings in the BIOS you need to power cycle the system (a simple reboot is not sufficient).
If this does not work, pleas post (attach) the virtual machine's vmware.log file.
André
PS: Discussion moved from VMware Workstation to Nested Virtualization