Addon no longer working - rendering T-bird & Lightning unusable Ohodnoceno 1 z 5 hvězdiček

What's going on? It took me a while to figure out that this addon (provider for google calendar) was rendering my Thunderbird/Lightning unusable/not responding. My google calendar xml URL appears not to have changed from before (I had to go into t-bird registry to see this since I can't enable Provider without crashing the application.)
I've tried killing/restarting countless times. I've removed and re-installed t-bird and add-ons - while not deleting the profile.
Any suggestions??