streaming video doesn't work with moonlight

Binary package hint: firefox

Source: http://www.rai.tv/dl/objects/silverlight/uniplayer/Rai.UniPlayer.xap
Width: 768px
Height: 466px
Background: #
RuntimeVersion: 3.0.40818.0
Windowless: no
MaxFrameRate: 25
Codecs: ms-codecs
Build configuration: debug, sanity checks

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: firefox 4.0.1+build1+nobinonly-0ubuntu0.11.04.1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic-pae 2.6.38.2
Uname: Linux 2.6.38-8-generic-pae i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Wed May 4 14:26:55 2011
FirefoxPackages:
 firefox 4.0.1+build1+nobinonly-0ubuntu0.11.04.1
 flashplugin-installer N/A
 adobe-flashplugin 10.2.159.1-0natty1
 icedtea-plugin 1.1~20110420-0ubuntu1
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)