Black screen upon starting up Kubuntu

[Keith Clark]

I have an up to date installation of Ubuntu/Kubuntu 10.04 Alpha 3 and I
cannot seem to start up Kubuntu.  It starts, I see the initial startup
screen, it fades to a black background.  Akonadi starts up fine but
turns black right after that.  I can hit Alt-F2 and the command window
pops up.  I can hit ctl-alt-del and the logout window pops up fine but I
cannot do much else as I cannot see any menu bars or backgrounds.

Any help would be appreciated.

Keith