Cannot open the disk 'D:\SOFTWARE\extract1\Mac OS X Lion Bootable .vmdk (For VMware)\Mac OS X Lion Installer.vmdk' or one of the snapshot disks it depends on. Reason: Failed to lock the file.

SOURCE: vmware mac Mac OS X 10.4

Yeah!  I got that a lot!  If you use virtual desktops sometimes it launches or is already launched, but on some other desktop that's not in focus.
  It turns out things just don't seem to be launching from the graphical interface; however, if you go into utilities and can get 'console' to launch you can see an error console that drops hints of why things aren't going smoothly.

  Usually some resource limit (which you can change to fix things) is being exceeded...virtual memory in use, for example.  Sometimes you just don't have the kind of CPU or videocard or Dock setup the program requires.

  You should be sure check out the Missing Manual by David Pogue, and run an antivirus scan sometime, too.  Salud!

SOURCE: how do i upgrade to mountain lion on my macpro1,1

Go to the App Store and purchase (or it is free) the upgrade, it's cheap! Apple.com