Thanks for the update, it does have to be a Windows computer. During the install procedure, it does not use the internet, so we can rule out any firewall issues.
The communications error means it is not detecting the BlackBerry during the multi-stage process.
That has been reported a number of times. Often, it will work if you run it again.
If it continues to fail at that point, we have to suspect a hardware problem in the device itself. That would be cause for having it replaced under warranty.