My code

Kraken.php

// php upload function

Array
(
    [file] => /tmp/phpRZl57f
    [wait] => 1
    [lossy] => 1
    [s3_store] => Array
        (
            [key] => xxxxxx
            [secret] => xxxxxx
            [bucket] => b.fitn.in
            [region] => ap-southeast-1
            [headers] => Array
                (
                    [Cache-Control] => max-age=2592000000
                    [Expires] => Wed, 11 Apr 2096 20:25:37 GMT
                    [Content-Type] => image/jpeg
                )

            [path] => f/c/1767_1419581132.jpg
        )

)

$original_response = Kraken::upload($original_upload_params);



// getting response 
Array
(
    [message] => Error while pushing file to S3: Expected params.Expires to be a Date object, ISO-8601 string, or a UNIX timestamp
    [success] => 
)