I didn't pay close enough attention to the failure and closed in prematurely.
There were two problems with the DNS test. One is that an IP I was using had changed so the DNS test was failing due to that. That was the problem I corrected.
One is that some releases of Net::DNS (0.76 and 0.79 I believe) there was a problem. Since I was running 0.74 on my computer, I didn't catch this.
On further investigation, this will be corrected in Net::DNS 0.80 (which is unfortunately not released at this time). The failure is only a warning, so it doesn't actually prevent the test script from running correctly. I'll investigate further and try to get a workaround in place.