Shark for Root not working

I am pretty much new to the **packet sniffing**. I found some application for the same **Shark for root**. I have rooted my phone for the application and I tried logging the packets being transferred from my mobile using the start button available in the application. But all in vain I was not able to log even a single packet, and All the time I open the .pcap file with the sharkreader It gives error as **Empty file opened**. I am using Android Gingerbread on my mobile. Also while stopping the logs, it gives some error executing some Shell commands like **killall**. Thanks in Advance.