moonlight plugin crash while loading video from rai.tv

Binary package hint: firefox

I'm unable to view some Silverlight content on site Rai.tv :-(

URL: http://www.rai.tv/dl/RaiTV/programmi/media/ContentItem-ff4d4e6e-4cd7-4d1c-9f67-68fb5d3aaee3.html
FireFox 4.0.1 on Ubuntu 11.04
Moonlight 3.99.0.3 with Microsoft Media Pack installed
Happens every time

Error:
Unhandled Error in Silverlight Application Value must be greater than zero at Mono.NativeMethods.dependency_object_set_value (IntPtr instance, IntPtr property, Mono.Value& value) [0x00000] in <filename unknown>:0
  at Mono.NativeDependencyObjectHelper.SetValue (INativeDependencyObjectWrapper wrapper, System.Windows.DependencyProperty dp, System.Object value) [0x00000] in <filename unknown>:0
  at System.Windows.DependencyObject.SetValueImpl (System.Windows.DependencyProperty dp, System.Object value) [0x00000] in <filename unknown>:0
File sorgente: http://www.rai.tv/dl/RaiTV/programmi/media/ContentItem-ff4d4e6e-4cd7-4d1c-9f67-68fb5d3aaee3.html
Riga: 0

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: firefox 4.0.1+build1+nobinonly-0ubuntu0.11.04.2
ProcVersionSignature: Ubuntu 2.6.38-9.43-generic 2.6.38.4
Uname: Linux 2.6.38-9-generic i686
Architecture: i386
Date: Sun May 15 06:47:43 2011
FirefoxPackages:
 firefox 4.0.1+build1+nobinonly-0ubuntu0.11.04.2
 flashplugin-installer 10.2.159.1ubuntu1
 adobe-flashplugin N/A
 icedtea-plugin 1.1~20110420-0ubuntu1
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 LANGUAGE=it_IT:en
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: firefox
UpgradeStatus: Upgraded to natty on 2011-04-29 (15 days ago)