Dealing with graphice pips

I plan allowing my game to beable to play on a few different computers. I read somewhere that doing the following would just fall back to using that pip instead, but instead,the whole thing just bugs out and crashes. How can we test for what pips safely?

load-display pandadx9
load-display pandadx8
load-display pandagl

  File "C:\Panda3D-1.7.2\direct\showbase\", line 561, in openWindow
  File "C:\Panda3D-1.7.2\direct\showbase\", line 494, in makeDefaultP
    "No graphics pipe is available!\n"
  File "C:\Panda3D-1.7.2\direct\directnotify\", line 132, in error
    raise exception(errorString)
StandardError: No graphics pipe is available!
Your Config.prc file must name at least one valid panda display
library via load-display or aux-display.
:TaskManager: TaskManager.destroy()

Also note, the error message is wrong as I can comment out the the first two and can load right into the program.

You have to use ‘aux-display’, not ‘load-display’, to list the alternate display library names.

You can only have one load-display, and this names the default. If you have more than one, only the first one is loaded.