@ISA and %EXPORT_TAGS must be package variables — globals. Otherwise, Exporter simply would never have access to them. Lexicals just won't work. Drop the "use strict" and both the instances of "my", and it works.

If you want to keep using strict, replace "my" with "our", or, if you want it to work on older perls too, add a line

use vars qw(@ISA %EXPORT_TAGS);
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and there is no longer a need for use of "our".