If you're installing 6.5, I'm guessing you have a valid software subscription and are eligible for support. If so, please also send mail to support@pipelinefx.com to open a helpdesk ticket.
In the meantime, you might try installing from the supervisor msi directly; it will be in the WIN32-5.0-x64 directory below the directory you specified during the QubeInstaller session.
- open a cmd prompt with 'Run As Admin'
- cd to the directory containing qube-supervisor-6.5-0*.msi
- run the following: msiexec /i qube-supervisor-6.5-0-WIN32-5.0-x64.msi
The install should complete normally. If not, open a support ticket with our helpdesk.