All tests are failing and there is Darren Chamberlain's module TOML, first released at the same day like Config::TOML. The latter should better be removed from CPAN to avoid confusion. Another module Config::Any::TOML, bridging Config::Any and TOML, however, would he helpful.
This module needs some better documentation, especially EXAMPLES how to make use of it. You have to dig into the source code to find out what it actually does. Normally you should only read the documentation (most people only read the SYNOPSIS and examples) and maybe the test cases (there are no test cases in 0.101). The current version does not invite you to invest your time to find out whether its worth a try.
This package is only a first public release from years ago that has sadly never been update. If you manage to get it installed and running at least you can parse MAB2 somehow. To make real use of it a refactoring is needed. The dependency of BerkeleyDB should be dropped with all the Tie::MAB2 classes. Instead a MAB2::Parser class is needed to parse a stream of MAB2 records (and deliver MAB2::Record objects either via a callback method or via a next() method). Such a parser and the MAB2::Record::* and Encode::MAB2::* classes are all you need. A pure-perl version would also be nice but the most urgentl part is to drop BerkeleyDB - that task of storing MAB2 should be independet from parsing and decoding it.