Hi Joe,
I downloaded the app attached to the issue and could not reproduce the problem in 6.2.4, neither in FF3 nor in IE7. To be sure, I also tested with my original app I stored locally, and could not reproduce there either in 6.2.4.
I suspect you might have caching problems. Try to download the sample app, delete bin, obj and ClientBin folders, remove references and rereference as well as upper to privteversion. Finally you should remove VWG files from C:\WINDOWS\Microsoft.NET\Framework\<Your relevant framework>\Temporary ASP.NET Files
See if you can still reproduce in your environment.
Palli