This module is an interesting idea in principle. It's yet more evidence to show that BioPerl is getting too big; hence alternative implementations are cropping up. On the downside, the exact differences between it and the Bio::DB::Taxonomy modules aren't entirely clear.
The documentation could be improved to clarify this, at which point the error (which is just a POD formatting error) that is showing up in the test reports could be addressed also.
It would also be handy if the interface mirrored that of BioPerl, so that it could be used as a drop-in replacement. And more tests should be added - if only to maintain the sanity of the developer/maintainer - right now, nothing of the actual API is being tested.