Ever since I upgraded to Ubuntu 8.10 the arrow keys in VMWare workstation are not mapped correctly. For example the down arrow key behaves like the Windows key, but only inside a VM (including the simulated BIOS). Outside of VMWare the keyboard behaves normally.

It turns out I was not the only one experiencing this. The solution is to add xkeymap.nokeycodeMap = true to your ~/.vmware/config file. You could do this from the command line with:
echo 'xkeymap.nokeycodeMap = true' > ~/.vmware/config but any text editor will do.

More information can be had from the VMWare forums