In response to your PM I had a look at the website.
the issue appears to be with detecting the mouse (down) event(s). there is info on which events (and how painfully long they take to run) on the the threads on here somewhere, webkit returns a very limited set on the kindle.
Simply put you would have to check for the correct events in the originating application. As other applications do actually work via webkit it is therefore possible to make this one work. However you would require access to the source and some testing knowledge to update the events handling to be more robust.
Hope that helps.