I had that issue with the .86 installer and in my case; the solution was to temporarily disable my firewall, IDS and antivirus.
YMMV though - I just figured I would share my personal experience as it is not unheard of for security products to cause such issues and I did not see that possibility mentioned.
Note: I did not report this issue as I am quite confident the issue I had was related to the version/instance of my firewall, antivirus or IDS and NOT with the install mechanism and/or web-server. The issue was clearly a configuration issue on my end.
FWIW - I am running:
- MBAM (Malware Bytes AntiMalware)
- Microsoft Security Essentials
- Private Firewall
I believe my issue was specifically the version/install of Private Firewall. I doubt I could duplicate it at this point as I upgraded it shortly after discovering that disabling all the above fixed the issue.