Warning: mkdir(/gallery/15th_December_2004): No such file or directory in /home/username/public_html/addgallery.php on line 25

Warning: mkdir(/gallery/15th_December_2004/thumbs/): No such file or directory in /home/username/public_html/addgallery.php on line 25
This is the error I get when trying to create a directory on my server.

Why isn't it letting me create the directory? When I tried it on my home server it worked fine.

Here is the PHP code for adding the gallery.

Addgallery.php
PHP Code:
<?php if (isset($_POST['cid'])){ 
    
include_once 
'includes/header.inc.php'?>

<div id="main">

<?php // a gallery has been added 

//add gallery

$cid $_POST['cid'];
$gallerydate $_POST['gallerydate'];
$gallerydate ereg_replace(" ","_",$gallerydate);

if (
$cid == '') {
    exit(
'<p>Please Choose a club.</p>');
    }

$sql "INSERT INTO gallery SET 
        gallerydate = '
$gallerydate',
        clubid='
$cid'";

 
if (@
mysql_query($sql)) {
        echo 
'<h3>Gallery Added.</h3>'mkdir ('/gallery/' $gallerydate0700); mkdir ('/gallery/' $gallerydate '/thumbs/'0700); chdir('./');
      } else {
        echo 
'<p>Error adding new gallery: ' .
        
mysql_error() . '</p>';
    }
?>

<p>Gallery Added</p>
<p><a href="gallery.php">See All Galleries</a></p>
<p><a href="addgallery.php">Add Another Gallery</a></p>
<p><a href="index.php">Return Home</a></p>

</div>

<?php include_once 'includes/footer.inc.php'; } else { 
    
    require 
'includes/secure.inc.php'
    include_once 
'includes/header.inc.php';
    
//show add gallery form ?>

<div id="main">

<h3>Add Gallery</h3>

<table>
    <form action="<?php echo $_SERVER['PHP_SELF'];?>" method="post">
        <tr><th>Club</th><td>
        
        <select name="cid" size="1">
        <option selected value="">Choose a Club</option>
        <?php $ok = @mysql_query("SELECT id, name FROM club ORDER BY name");
            if (!
$ok)
            {
            exit (
'<p>Error performing query: ' mysql_error() . '</p>');
            }
            while (
$row2 mysql_fetch_array($ok))
            {
            
$id $row2['id'];
            
$name $row2['name'];

            echo 
"<option value=\"$id\">$name</option>"; }?>

        </select></td></tr>

        <tr>

        <th>Date:</th><td><input type="text" name="gallerydate" size="30" /></td></tr>
        
        <tr><td></td><td>
        <input type="submit" value="Add Gallery" class="submit" /></td></tr>
        </form>
</table>

</div>

<?php include_once 'includes/footer.inc.php'; } ;?>
The error claims to be in this line

echo '<h3>Gallery Added.</h3>'; mkdir ('/gallery/' . $gallerydate, 0700); mkdir ('/gallery/' . $gallerydate . '/thumbs/', 0700); chdir('./');
Any help would be much appreciated.