k3b locks when trying to burn DVD iso file

Using Kubuntu 7.10. Burned an iso file yesterday on CD. Worked fine. Later when I attempted to burn a different iso file selecting DVD instead, my HD light comes on and stays on and my screen freezes, mouse stops, "control-alt-delete" does not back me out.

I tried loading the blank DVD first and beginning K3b from the automatic popup screen, but when I select burn iso DVD it locks. I tried starting from an opened K3b first, then selecting burn DVD iso and the same thing happens, a total system lockup.

The only way that I can get active again is to do an emergency reboot which I know is not the best way to close the system. I have also tried to delete K3b and reinstall it and that has not helped.

If you wish a copy of a file or some other information just ask. Offer directions on how to access what you ask, just in case it is something beyond my current understanding.