Are there any errors BEFORE the -65545?
The 65545 means that mdns wasn’t initialized, but I don’t know why it failed to initialize. There should be an error message before that. This is a 32bit intel box, right? Not something esoteric like AMD64 or an ARM box or something, right?
Did you run the netstat to make sure you weren’t running some other mdns process? I really suspect this.
As far as the firewall issue goes, did you merely turn it off, or did you add the rules to allow multicast traffic? And did you stop and uninstall Howl?