Sorry to hear you are not able to connect to Home Sharing on your iPad. I found an article that has steps for troubleshooting Home Sharing. You can skip any of the steps that you have already done and the ones that do not relate to the iPad (like checking Firewall Settings).
If you are still getting the same error, "Unable to connect to Home Sharing," you can try restarting your iPad and then continue with resetting your iPad if the error persists:
Resetting your device
Press and hold the Sleep/Wake button and the Home button together for at least ten seconds, until the Apple logo appears.
You can find the full article here: