I think you may find Cisco files in a LaunchAgent folder.
There's a minimum of 3 places to look for those:
There's several other possibilities, such as Applications Support folders, LaunchDaemons folders, etc.
I suspect that the Cisco software is coded to expect to be loaded at login to work properly - so, my question: Why is it important for you to prevent the Cisco VPN software from loading at login? Does it interfere with some other connection protocol that you may be using?
Serendipity is a lucky guess !