The "Cannot get the official hostname" error seems to only show up on a small number of machines and we haven't figured out yet what the reason for this is (see
here).
For now I would suggest the following temporary workaround:
- open the Terminal (in /Applications/Utilities)
- paste "sudo hostname mydnsdomain" and hit return
- then enter your admin password and hit return again
Unfortunately, you have to do this after each reboot of OS X until we provide a fixed version. On the positive side you are not making any permanent changes to your system with this workaround.