"Unable to connect to Parallels Service.
Make sure that the prl_disp_service process is active and it is not blocked by Firewall. For details, please refer to http://kb.parallels.com/en/8089. If the problem persists, contact the Parallels support team for assistance."
no need to worry. All you need to do is open Terminal, stop and restart Parallels:
sudo launchctl stop com.parallels.desktop.launchdaemon
Then restart it:
sudo launchctl start com.parallels.desktop.launchdaemon
If you run the following command now:
sudo launchctl list | grep com.parallels.desktop.launchdaemon
The output should be something like this:
94248 - com.parallels.desktop.launchdaemon
Try again, should be okay now.