Index: engines/apc.php
===================================================================
--- engines/apc.php	(revision 14548)
+++ engines/apc.php	(working copy)
@@ -119,7 +119,7 @@ class apcCache extends Cache {
       $key = substr($key, 0, strlen($key) - 1);
       $lookup = apc_fetch($this->lookup);
       foreach ($lookup as $k => $v) {
-        if (substr($k, 0, strlen($key) - 1)) {
+        if (substr($k, 0, strlen($key) - 1) == $key) {
           apc_delete($k);
           unset($lookup[$k]);  
         }