I've Just click on the remove link (in the G-mail sample) after several document was upload.
And then IHM is reset, lost all other upload document in your Control.
I've trying this sample on 2 computers (dev and server) and i still have the same problem.
I've used the web application in the folder : Framework 1.x-Csharp
I do not change any line of your sample and web.config.