Pause Host and HTML engines and stop the web server in ADGate. Quit ADGate. Move it to the trash, empty it and make sure nothing is left there. Copy the new version of ADGate to disk. Start it and fill in your admin password.
That is all.

This problem is fixed in version 3.2.0.
A bug in the registration code makes ADGate match all DNS lookups to localhost, if and only if pirated serie numbers are used. To fix this, quit ADGate and remove com.li.hao.adhelper.plist in your home/Preferences folder and restart.

In unregistered version, you cannot add or remove URL and Host patterns, so on some sites, you may notice no or few changes. You can go to http://www.macsurfer.com to check the effects by turn on and off engines in ADGate and refresh the page in browser.