There are some video cards that have trouble booting into the graphical installation program. If the installation program does not run using its default settings, it tries to run in a lower resolution mode. If that still fails, the installation program attempts to run in text mode.
One possible solution is to try using the resolution= boot option. This option may be most helpful for laptop users. Another solution to try is the driver= option to specify the driver that should be loaded for your video card. If this works, it should be reported as a bug as the installer has failed to autodetect your videocard. Refer to Chapter 9, Boot Options for more information on boot options.
To disable frame buffer support and allow the installation program to run in text mode, try using the nofb boot option. This command may be necessary for accessibility with some screen reading hardware.