Hi, below is my test result:

System: Win 8.1 + WinPcap 4.1.3
WiFi: Qualcomm Atheros AR5BWB222 Wireless Network Adapter
URL Snooper 2.33.01 doesn't work
WinDump 3.9.5 tested OK
basic_dump.exe tested OK
URL Helper 3.42 works without problem!
HiDownload 8.24 built-in sniffer works!
StreamTransport 1.1.4.0, not winpcap-based, but works.

I've had great experience with URL Snooper while sticking with old XP/Win7 laptops. I hope the next release of URL Snooper will fix the WiFi detection issue.