my $modulePath = $INC{'Chess/PGN/EPD.pm'};

##</code><code>##

...
use File::Spec::Functions qw(rel2abs splitpath updir catdir);
use Cwd qw(realpath);

my $loadPath   = rel2abs ($INC{'Chess/PGN/EPD.pm'});
my @parts      = splitpath ($loadPath);
my $db_dir_qfn = realpath (catdir (@parts[0, 1], updir(), 'db'));