PHP upload error

Colleagues.

I have a challenge that I can not understand. I have the following simple Upload code:

  list($arquivo, $extensao) = explode(".",$arquivoNome);
  $codificar = md5(date('h:i').$arquivo).".".$extensao;
  $dirArquivo = "uploads/pdf/";
  $upArquivo = $dirArquivo . basename($codificar);
  move_uploaded_file($arquivoTemp, $upArquivo);  

The file goes correctly to the folder, however when I try to do a check:

if (move_uploaded_file($arquivoTemp, $upArquivo){
   // Ok...vamos gravar...
}else{
  exit("Erro " .UPLOAD_ERR_CANT_WRITE);
}

The value returns 7, ie it fails to write the file to disk, but how does the file go correctly to the folder?