If you're trying to use Wireshark to sniff/analyze ZigBee traffic collected with the CC2531 TI Packet Sniffer software/drivers, you'll also need to install the "Wireshark Packet Converter". I couldn't find that Wireshark Packet Converter, or TiWsPc.exe on the TI site but discovered that it's bundled with the TiMac software which you can download from http://www.ti.com/tool/TiMac. So there's your breadcrumb for how to find that piece of software.