Issues upgrading to V3 (solved)

Just in case anyone else gets issues upgrading to V3...
I downloaded the demo version OK and it replaced my V2 prefpane OK
Went to website and purchased the update OK
Downloaded the new license file OK
Double-clicked the license file
Hazel prefpane opened and I noticed the expiry date hadn't changed, and Hazel had stopped running
Clicking the 'Start Hazel' button didn't do anything
I thought I might uninstall and reinstall, but running in demo mode doesn't allow you to export your rules (why?)
Repeating the double-click on the license file didn't do anything
Tried dragging the license file onto the Hazel window and this worked. Hazel now registered, but still not running.
Checking the Hazel log revealed that Hazel was having trouble talking to the helper application, so I opened up Activity Monitor and quit the HazelHelper application. This time when I pressed the 'Start Hazel' button, it started up OK and is now running normally.
I downloaded the demo version OK and it replaced my V2 prefpane OK
Went to website and purchased the update OK
Downloaded the new license file OK
Double-clicked the license file
Hazel prefpane opened and I noticed the expiry date hadn't changed, and Hazel had stopped running
Clicking the 'Start Hazel' button didn't do anything
I thought I might uninstall and reinstall, but running in demo mode doesn't allow you to export your rules (why?)
Repeating the double-click on the license file didn't do anything
Tried dragging the license file onto the Hazel window and this worked. Hazel now registered, but still not running.
Checking the Hazel log revealed that Hazel was having trouble talking to the helper application, so I opened up Activity Monitor and quit the HazelHelper application. This time when I pressed the 'Start Hazel' button, it started up OK and is now running normally.