--- private_upload.module.orig	2010-05-31 14:51:12.000000000 +1200
+++ private_upload.module	2010-05-31 14:54:26.000000000 +1200
@@ -360,7 +360,7 @@ function private_upload_form_alter(&$for
           $description = "<small>". check_plain($href) ."</small>";
           $form['attachments']['wrapper']['files'][$fid]['description'] = array(
             '#type' => 'textfield', 
-            '#default_value' => (strlen($file->description)) ? $file->description : $file->filename, 
+            '#default_value' => (drupal_strlen($file->description)) ? $file->description : $file->filename, 
             '#maxlength' => 256, 
             '#description' => $description, 
           );
@@ -704,7 +704,7 @@ function _private_upload_starts_with( $s
  * @return string: the modified string.
  */
 function _private_upload_replace_start_with( $str, $start, $new ) {
-  return substr_replace( $str, $new, 0, strlen($start) );
+  return substr_replace( $str, $new, 0, drupal_strlen($start) );
 }  
 
 /**