My system is based on MacOS, so I needed to press and hold 'C' at the VMWare BIOS screen, much like a normal Mac.
My whole rigmarole is here in case someone else finds this article for the same reasons I found it:
I recently grew my MacPro VM's virtual disks from 128G to 256G, and ran 'sudo diskutil resizeVolume / R' to try to make the space available, but it told me 'MediaKit reports partition (map) too small'.
I downloaded gparted-live-0.27.0-1-i686.iso and put it into datastore1, added it 'at power up' to the VM's CD, changed the VM type to Other 2.6.x LInux 32 bit, booted the VM and held C down from the VMWare screen until it reached the GRUB screen, but while I could select the GRUB options, most of the resulting systems either didn't recognise the keyboard in character mode, or the mouse in GUI mode.
Every so often, the default GRUB option worked but while I got through language selection I found I needed to leave the GUI alone for quite a while - perhaps scanning the disk - before the it recognised the keyboard or mouse clicks.
I told it to fix the partition table - the 'do you want to fix this' that came up automatically.
I saw a small /dev/sda1, the EFI system partition, at 200M, /dev/sda2 the Mac HD, at 127G, /dev/sda3 the recovery HD at 620M, and 128G of unallocated space.
I asked to move the recovery partition to the very end of the free space, and it said that might be bad, so I just quit and rebooted.
I turned the guest OS back to Mac (I had to log in to the host as root to shut down the VM, for some reason: VMWare Fusion didn't give me the shutdown option), and now it's back in OSX.
Now resizeVolumes / R doesn't show the
'Note: Your partition map does not use the entire space of your whole-disk' warning, and completes without 'MediaKit reports partition map too small'.
And my HD is at 274G. not quite the whole 128G, but certainly better than 127.