The last successful weather call does not have a valid value meaning the device is not getting a reply. This could be a network issue such as a firewall which we have seen in the past. Do you have anything unique about your network setup possibly?
I would request a new key from wunderground.
Make sure you follow the opensprinkler article when requesting.
I remember there was a couple of tricky things when requesting a key.
I would double check IP address, subnet mask, Gateway and DNS settings on your opensprinkler as well.
I know you can check IP address from the panel. Not sure it comes up with other information.