"Comodo Security Agent could not be started" message on start up

Sometimes on starting my 32 bit vista I get an alert popup “Comodo Security Agent could not be started” with an option to run diagnostics… Why does it only happen sometimes?if i had disabled it by mistake it would always happen

What is the difference between Comodo Security Agent and CIStray.exe . Cistray.exe is usually runing when i get the alert

I am having same problem.