In Fusion 5.x and below, you cannot shut down / power off virtual machines that are suspended. Virtual machines must first be turned on, and then shut down. For more information, see
Working with power options in VMware Fusion (1018242).
In Fusion 6.x and above, you can force shutdown a suspended virtual machine by pressing the Option Key on the keyboard and selecting Force Shutdown in power options.
In Fusion 4.x and later, you can also click Virtual Machine > Shut Down in the menu bar and a pop up will reveal the options to shut down normally or to force shut down.