Hi nhuda,
1. Please try the link below, it should show you the debug info in top right when you upload file. Please show me all debug info.
http://www.casadata.org/test/Default.aspx?UploaderDebug=1
2. try disable all plugins of the browser.
3.Disable all Anti-virus software and firewall to try again. (your test pc, not the server)
Keep me posted.
Regards,
ken