VoIP RTCP Packets

I'm doing a project that consists of monitorization of RTP/RTCP traffic
between two computers that run windows messenger.

The problem is that the site of Microsoft says that they follow the
RTCP specification but in most RTCP packets all the info is garbage...
even the NTP Timestamp of RTCP Sender Report packets gives me overflow
while trying to convert to DateTime.

Does anyone understands this protocol? Why doesn't Microsoft follow
their own specification of RTCP packets?

Thanks for any reply,
Nuno Magalhaes.