I've been spending increasingly more time researching topics for Unix Tutorial on one of my desktops. Ubuntu has replaced the Windows Vista I had and so far I quite like the experiment. Out of the box, all of the hardware was properly supported and even the NTFS partitions left from Vista install are easily available.
One of the first things I've decided to install was the trial version of the latest VMware Workstation: 6.0.3 build-80004. And although it installed without a problem, when I tried to run one of the previously created virtual machines, I got the following error:
VMware Workstation unrecoverable error: (vcpu-0)
Failed to allocate page for guest RAM!
As it turned out after a quick investigation, that was a result of running a VM from a NTFS partition, because its default mounting settings don't have the exec option.
Since you shouldn't be running anything critical through an NTFS driver anyway, I simply moved the VM onto one of the ext3 partitions and, sure enough, it fixed the guest RAM allocation error.
Update: if your scenario prevents you from moving a VM to a native partition, use the following option:
mainmem.UseNamedFile = "FALSE"
You should add it to the vmx file of your VM. Thanks for the tip, benito!