looks like i need to fix some version info inconsistencies.
your guess about the problem is the most likely explanation - that is that it is a winpcap incompatibility with your modem hardware.
what kind of modem do you have? if you are not seeing the countiner of packets then for sure its detecting any packets.
try searching winpcap support page: http://www.winpcap.org/contact.htmHOWEVER:
my understanding is that ethereal uses winpcap,
so if ethereal works then i think there is no reason that url snooper shouldn't!
can you compare the network card selection list in both programs, see if they are the same or similar, make sure you have the proper card selected.
reboot your computer to make sure it has a chance to register the new winpcap drivers.
please do give us a follow up after trying these things - like i said if ethereal uses winpcap and works then there is absolutely no reason why url snooper shouldn't work.