Works for me, or at least generates the following output which I guess is right:

 2013/03/27, 03:35 PM - Now in Seconds is: 1364351700
 Test: High Tide at: 12:21 AM
 Test: Low Tide at: 06:20 AM
 Test: High Tide at: 12:50 PM
 Test: Low Tide at: 06:39 PM

 Option 3
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Note that I changed the file read line to:

local $/;
my $data = $xml->XMLin(<DATA>);
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and put the data in a __DATA__ block to save generating a file in addition to the script.