> perldoc Win32::API

Note that "Import" returns 1 on success and 0 on failure (in which case you can check the content of $^E).

So there's a good chance that is also useful if new() fails:

my $idleTrackerInitHand­le = Win32::API->new(
        "C:\\Perl\\dvl\\itun­es\\IdleTrac.dll", "int IdleTrackerInit()
+"
    )
    or  die "Can't import IdleTrackerInit: $^E\n";
[download]

And solve whatever problem this points to.