"Unknown error" running consolehelper

[knighttof3]

I cannot configure my display using the System > Administration > Display menu. The launcher shows it is waiting for a while, then dies.
I right-clicked on the launcher and copied it to my desktop. For good measure, I did the same for the Keyboard launcher. Clicking on properties for both, they are /usr/bin/system-config-display and /usr/bin/system-config-keyboard respectively; and those two are symlinks to consolehelper.
Trying to "sudo /usr/bin/consolehelper" pops up a dialog saying Unknown Error. Maybe this is expected.
The funny thing is, System > Administration > Keyboard works fine. "sudo /usr/bin/system-config-keyboard" works fine.
"sudo /usr/bin/system-config-display" gives a Python exception:

Traceback (most recent call last):
File "/usr/share/system-config-display/xconf.py", line 381, in ?
dialog = xConfigDialog.XConfigDialog(hardware_state, xconfig, rhpxl.videocard.VideoCardInfo())
File "/usr/share/system-config-display/xConfigDialog.py", line 532, in __init__
self.state.recalc_mode()
File "/usr/lib/python2.4/site-packages/rhpxl/xhwstate.py", line 390, in recalc_mode
self.colordepth = availableDepth[-1]
IndexError: list index out of range