PHP date () does not return the correct date / time

The code below...

$date = "02-13-2012";
$start_time = "17:30";
$end_time = "20:00";

$start_timestamp = date("m-d-Y H:i",strtotime($date." ".$start_time));
$end_timestamp = date("m-d-Y H:i",strtotime($date." ".$end_time));

print($start_timestamp);
print($end_timestamp);

Returns...

1969-12-31 19:30:00

1969-12-31 20:30:00

Does anyone have any idea why this is not working correctly?

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See this. I think you have to change the date format.

$date = "02-13-2012";
$date = str_replace("-","/",$date);
$start_time = "17:30";
$end_time = "20:00";

$start_timestamp = date("m-d-Y H:i",strtotime($date." ".$start_time));
$end_timestamp = date("m-d-Y H:i",strtotime($date." ".$end_time));

print($start_timestamp);
echo "<br/>";
print($end_timestamp);