Here's a solution that uses the core module Time::Local

use Time::Local qw( timegm );

/(\d{4})[-\/.](\d{2})[-\/.](\d{2})/
  or die("Bad format\n");

my $time = eval { timegm(0, 0, 0, $3, $2, $1) };
die("Bad date\n") if $@;
[download]

Switch timegm for timelocal if you prefer.