single mode boot doesn't work because the error takes place before it's complete.If this was a physical server I would boot from a USB stick, network or DVD/CD but being a VM I don't know what to do.
Why don't you boot the Virtual Machine from a Linux Live CD/DVD/ISO Image and edit the file that way? Either use the ISO Image you created the Virtual Machine from or one Linux Distro I like to use in a rescue scenario is Slax.
You can change the Boot Order from the Virtual Machine Settings > Advanced > Startup Device in VMware Fusion 3.x.