Erro ao inserir com PDO

Usando Silex e PDO, via post "aceito" o seguinte formato:

{
"softwares": [{
"server": "srvteste13",
"binary": "phantomjs",
"software": "phantomjs",
"daemon": "phantomjs.d",
"path": "/usr/bin",
"version": "1.0"
}, {
"server": "srvteste13",
"binary": "teste2",
"software": "teste2",
"daemon": "teste2.d",
"path": "/var/www/teste2",
"version": "2.0"
}, {
"server": "srvteste13",
"binary": "php",
"software": "php",
"daemon": "php.d",
"path": "/usr/bin",
"version": "5.6"
}, {
"server": "srvteste13",
"binary": "HTTP",
"software": "APACHE HTTP",
"daemon": "HTTP.d",
"path": "/usr/bin/apache2",
"version": "2.0"
}, {
"server": "srvteste13",
"binary": "phantomjs",
"software": "phantomjs",
"daemon": "phantomjs.d",
"path": "/bin",
"version": "2.38"
}, {
"server": "srvteste13",
"binary": "DANIEL",
"software": "DANIEL",
"daemon": "DANIEL",
"path": "DANIEL",
"version": "DANIEL"
}]
}

No bd, há uma relação entre tabela por isso o insert com select, segue:

$app->post('/softwares', function(Request $request) use ($app, $dbh) {
 $data = json_decode($request->getContent(), true);

 if(isset($data['softwares'])){

$sth = $dbh->prepare("INSERT INTO softwares(HARDWARE_ID, PUBLISHER, NAME, VERSION, FOLDER, COMMENTS, FILENAME, FILESIZE, SOURCE, GUID, LANGUAGE, INSTALLDATE, BITSWIDTH) SELECT id, NULL, :software, :version, :path, NULL, :binary, NULL, NULL, NULL, NULL, NULL, NULL FROM hardware where hardware.name = :server");

 for($i=0; $i < sizeof($data['softwares']); $i++){
 $sth->execute($data['softwares'][$i]);
 $id = $dbh->lastInsertId();
 }

 // response, 201 created
 $response = new Response('Ok', 201);
 $response->headers->set('Location', "/softwares");
 return $response;

 }else{
 $response = array("status" => 400, "code" => 400, "message" => "invalid json format");
 return new Response(json_encode($response), 400);
 }
});

 Se eu der um print_r em $data['softwares'] está assim:

Array
(

 [softwares] => Array
 (
 [0] => Array
 (
 [server] => srvteste13
 [binary] => phantomjs
 [software] => phantomjs
 [daemon] => phantomjs.d
 [path] => /usr/bin
 [version] => 1.0
 )

 [1] => Array
 (
 [server] => srvteste13
 [binary] => teste2
 [software] => teste2
 [daemon] => teste2.d
 [path] => /var/www/teste2
 [version] => 2.0
 )

 [2] => Array
 (
 [server] => srvteste13
 [binary] => php
 [software] => php
 [daemon] => php.d
 [path] => /usr/bin
 [version] => 5.6
 )

 [3] => Array
 (
 [server] => srvteste13
 [binary] => HTTP
 [software] => APACHE HTTP
 [daemon] => HTTP.d
 [path] => /usr/bin/apache2
 [version] => 2.0
 )

 [4] => Array
 (
 [server] => srvteste13
 [binary] => phantomjs
 [software] => phantomjs
 [daemon] => phantomjs.d
 [path] => /bin
 [version] => 2.38
 )

 [5] => Array
 (
 [server] => srvteste13
 [binary] => DANIEL
 [software] => DANIEL
 [daemon] => DANIEL
 [path] => DANIEL
 [version] => DANIEL
 )

 )

)

o erro(warning, não erro, porém não insere) que me retorna é:

Warning</b>: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens.

Retorna 6 linhas com esta mensagem, devido ao loop do indice do array enviado via rest.

Já estou a tempos tentando achar o problema e nada, agradeço aos que puderem me dar uma luz.