Solved! Go to Solution.
I noticed that you said you're using Ethereal. This is somewhat OT, but have you tried Wireshark. AFAIK, there has been no development on Ethereal for ages and Wireshark is the continuation of what was Ethereal by much (if not all) of the team that used to do Ethereal. The name change is explained on the wireshark website (http://www.wireshark.org/). It uses much more recent versions of WinPcap too, so that might help.