I get the same flashing white poping thing as well. It drives me nutz and I get it on all of my touweaver 2.0 panos. I have looked at the same tours on systems running older versions of java with lower resoulution monitors and they did not diplay the same white flashing. The flashing and poping only happen when the tour is being rotated not when it is stoped or stationary.
I dont know if its tourweavers buggyness with the newer version of Java or some kind of display difficulty with various resoultion of monitors. I have a dell 20.2 ultrasharp 1600X1200 LCD run at 32bit & an Nvidia 6800gt running on Windows XP. I have the latest version of Tourweaver 2.0 (AKA buggy as I affectionately call it). I have yet to find a fix and I seriously doubt there will be one. If you find something that works I would love to hear about it.
Steve check out my tour and see if you see the same white flashing.
Best of luck to you.