I have a form:

<form enctype="multipart/form-data" action="upload.php" method=post>
Upload a file:<br>
<input name="file" type="file"><br>
Subfolder(s) (Optional):<br>
<input name="folder" type="text"><br>
(Media is automatically arranged under the following categories: "music", "pics", "video", "other"; and subfolders are organized within those folders.)<br>
<input type="submit" value="Send File"></form>

and I have the upload code:

if ($_FILES['file']['size'] < 20971520)
  {
  if ($_FILES['file']['error'] > 0)
    {
    echo "Error: " . $_FILES['file']['error'] . "<br />";
    }
  else
    {
	if ((eregi(".php", $_FILES['file']['name'])) || (eregi(".aspx", $_FILES['file']['name'])) || (eregi(".asp", $_FILES['file']['name'])) || (eregi(".htm", $_FILES['file']['name'])) || (eregi(".html", $_FILES['file']['name'])) || (eregi(".jsp", $_FILES['file']['name'])) || (eregi(".cfm", $_FILES['file']['name'])) || (eregi(".vb", $_FILES['file']['name'])) || (eregi(".js", $_FILES['file']['name'])) || (eregi(".mht", $_FILES['file']['name'])) || (eregi(".cgi", $_FILES['file']['name']))) {
	die("Please upload in .txt format");
	}
	else {
	if (($_FILES['file']['type'] == "image/gif") OR ($_FILES['file']['type'] == "image/jpeg") OR ($_FILES['file']['type'] == "image/pjpeg") OR ($_FILES['file']['type'] == "image/png") OR ($_FILES['file']['type'] == "image/bmp") OR ($_FILES['file']['type'] == "image/x-emf")) {
	$medium = "pics";
	}
	elseif (($_FILES['file']['type'] == "audio/mpeg") OR ($_FILES['file']['type'] == "audio/x-ms-wma") OR ($_FILES['file']['type'] == "audio/wav")) {
	$medium = "music";
	}
	elseif (($_FILES['file']['type'] == "video/avi") OR ($_FILES['file']['type'] == "video/x-ms-wmv") OR ($_FILES['file']['type'] == "video/quicktime")) {
	$medium = "video";
	}
	else {
	$medium = "other";
	}
	if (!($_POST['folder'] = "")) {
		if (eregi('^/' , $_POST['folder'])) {
		$subfolder1 = substr($_POST['folder'] , 1);
		}
		else {
		$subfolder1 = $_POST['folder'];
		}
		if (!(eregi('/$' , $_POST['folder']))) {
		$subfolder2 = $subfolder1 . "/";
		}
		else {
		$subfolder2 = $subfolder1;
		}
		$subfolder = $subfolder2;
	}
	else {
		$subfolder = "";
	}
    if (file_exists("files/" . $_SESSION['s_username'] . "/" . $medium . "/" . $subfolder . $_FILES['file']['name']))
      {
      echo $_FILES["file"]["name"] . " already exists.  You should rename it.";
      }
	else
      {
		if (!(file_exists("files/" . $_SESSION['s_username'] . "/" . $medium . "/" . $subfolder))) {
			mkdir("files/" . $_SESSION['s_username'] . "/" . $medium . "/" . $subfolder); }

move_uploaded_file($_FILES["file"]["tmp_name"],
      "files/" . $_SESSION['s_username'] . "/" . $medium . "/" . $subfolder . $_FILES['file']['name']);
	  echo "Name: " . $_FILES['file']['name'] . "<br />";
      echo "Type: " . $_FILES['file']['type'] . "<br />";
      echo "Size: " . ($_FILES['file']['size'] / 1024) . " KB<br />";
      echo "Stored in: " . "/files/" . $_SESSION['s_username'] . "/" . $medium . "/" . $subfolder .  $_FILES['file']['name'];
	  echo '<br><a href="/index.php" title="Main Page">Return to the Main Page</a>';
      }
    } }
  }
else
  {
  echo 'Your file is bigger than 20 MB.  Please use the <a href="_URL_" title="FTP Server">FTP Server</a> to upload the file.  If you don'."'".'t, the likelihood that the file will actually be uploaded depends on how good a connection there is between the server and your computer, which is not, likely, high enough.';
  }

See the form's 'folder' input?
and the $subdirectory part of the script?
I want to make that work.
My upload script automatically organizes uploads into one of four files: music, pics, video, or other; of a user's folder by alias.
so blah.jpg uploaded under username flux goes to:
/files/flux/pics/blah.jpg
But with the subdirectory I want to give my users the ability to add directories, like so:
username flux
file blah.jpg
subdirectory "etc/directory/"
which should cause the file to be saved under:
/files/flux/pics/etc/directory/blah.jpg
I've noticed after echoing $_POST['folder'] in various parts of my script that it reads fine immediately after saving the file, but it reads as " " otherwise. Anybody know why and how to fix it? Is it a php.ini thing..?
Thanks in advance.
Edit: Does anyone know...?...