I'm not with Laminar Research, just a fellow simmer in the UK.
A couple of possible causes regarding the 'permission denied' message:-
1. You have anti virus software installed and the firewall is preventing XP11 from accessing the relevant drive?
2. The user permissions set up for the drive upon which XP11 is to be installed, require adjustment?
3. You are not installing XP11 on the PC's desktop or in the root folder of a logical drive i.e. C:\X-Plane 11
4. I do not believe that downloads from Laminar Research's website are zip compressed, so what 'zipped update' are you trying to install