10.8.5 is not currently a supported OS - http://kc.mcafee.com/corporate/index?page=content&id=KB68921#Supported_Mac_OS so I imagine its blocking - there may be a note in the log.
You may want to step through "For Systems that fail to become active" in http://kc.mcafee.com/corporate/index?page=content&id=KB72604
the logs and steps there may reveal something.
Thanks for your reply, i have that same document and am aware that the new 10.8.5 is not going to be part of the supported OS's at this time. What i was hoping for is if anyone has had and issues with their own installs thus far and if they have got it to work if they could pass on some tips to get the install done. I have opened a ticket with mcafee which did not amount to anything as the tier 1 guy could not provide me with much info. I am doing some testing on my own side to see what happens but i can say for certain that i am not having success in getting the extensions install if the client has already done the 10.8.5 update. comes back with an unsupported error.