I have the same problem with Cisco VPN version 4.8.XXX aand 5.0.XXX. I fixed the problem by going to registry, HKLM and HKCU and search for anything related to "Cisco" and remove these entries. Run the vpnclient_setup.exe program and now windows installer show up. If it failed to install the Deterministic Network portion then download the latest driver from Deterministic website, run setup and reinstall VPN client again.
Normally in a scenario like yours. what you do is assuming that you only the Cisco VPN client as the only Cisco Software installed, go to the registry and delete any key,hkey or dword starting with Cisco.
if you are familier with the registry editor try and use a software registry cleaner.
you might also want to backup the registry before you make the changes.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...