I recently tried to install VMWare’s tools into a 64-bit FreeBSD in VMware Workstation 8.  I was unable to get the tools provided by VMware to install.  A quick Google search showed this is a common problem.
The solution is to use the VMware tools provided in the ports collection.  Even this method requires some minor tweaking though.
The process:

  1. If you haven’t already, install the ports collection.
  2. From VMware Workstation’s VM menu (right-click in Vsphere), choose “Install VMware Tools…”.
  3. In the FreeBSD VM, determine which device is your CD drive.  It’s always been /dev/cd0 in my VMs but you’ll want to double-check.
  4. Before installing the VMware tools port, you need to update the Makefile /usr/ports/emulators/vmware-guestd6/Makefile.  Update the line MOUNT_DEV? = /dev/ad0 to point to your cdrom.  Mine looks like MOUNT_DEV? = /dev/cd0
  5. Change to the /usr/ports/emulators/vmware-tools6 and run the make command.  You’ll be prompted to continue.  Say yes.

If all goes well, the port will access the cdrom, grab some files, download more files and build the tools.  The tools are installed in /usr/local like most ports.
If you plan to run X11, you may also want to install the VMware X11 driver in /usr/ports/x11/drivers/xf86-video-vmware.  It will install the Vmware specific video driver.
03/05/2012 Update:  After few reboots, the errors returned.  See this post in the VMware forums for details: http://communities.vmware.com/message/1893843