The ChmodBPF script supplied with the WhatPulse client installer on Mac OS, is a script to provide your local user with read access to so-called bpf devices (/dev/bpf*). Without these read access rights, WhatPulse cannot measure your network statistics. The permissions of these bpf devices are reset upon system startup, which is why we supply a startup script (/Library/StartupItems/ChmodBPF) with the installer.
If you do not want these permissions changed and can live with WhatPulse not being able to measure your network traffic, you can safely delete the folder /Library/StartupItems/ChmodBPF.
If you have accidentally removed the startup folder and want to restore it, without reinstalling the client, download the startup folder here.
Unzip the file inside /Library/StartupItems and change the owner to root. (chown -R root /Library/StartupItems/ChmodBPF). This should set the proper permissies the next time you restart your computer.