Index: engines/file.php
===================================================================
--- engines/file.php	(revision 0)
+++ engines/file.php	(working copy)
@@ -110,11 +110,11 @@
       // Filename: abcdef12345verylongmd5code--content:123456:987654
       $files = file_scan_directory($fspath, ".--$look_for[0].", array('.', '..', 'CVS'));
       foreach ($files as $file) {
-        if ($fp = fopen($file, 'w')) {
+        if ($fp = fopen($file->filename, 'w')) {
           // only delete the cache file once we obtain an exclusive lock to prevent
           // deleting a cache file that is currently being read.
           if (flock($fp, LOCK_EX)) {
-            unlink($file);
+            unlink($file->filename);
           }
         }
       }