This message typically comes right after you've installed VMware tools inside a linux guest. VMware tools will at the end of it's process eject the virtual cdrom where the tools are located and this is something the guest os doesn't like since the cdrom is mounted to it's file system.

The solution is:

1. Select "Install VMware Tools" once again from the VM drop down menu.
2. Unmount the virtual cdrom device. Typically with the command umount /media/cdrom
3. Select "VM" / "End VMware Tools Install"