That is the error message you will get from ISC Bind (DNS) when you have something wrong with a lookup file. In my case it was a problem with my reverse lookup zone file. I had made the reverse records A records instead PTR (pointer) records. Fixed that and it started working!
From doing research on my issue, this can also happen for missing a period or using a comma instead of a period, etc. To me the error message is a bad description for my problem. My dots were okay, it was just the record types. think they should change it.