There is a typo when throwing the exception that tags are not supported by the backend.

Patch against current trunk:

Index: Zend/Cache/Core.php                                         
===================================================================
--- Zend/Cache/Core.php (revision 21978)                           
+++ Zend/Cache/Core.php (working copy)                             
@@ -475,7 +475,7 @@                                                
             Zend_Cache::throwException(self::BACKEND_NOT_IMPLEMENTS_EXTENDED_IF);
         }                                                                        
         if (!($this->_backendCapabilities['tags'])) {                            
-            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORT_TAG);           
+            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORTS_TAG);          
         }                                                                        
                                                                                  
         $ids = $this->_backend->getIdsMatchingTags($tags);                       
@@ -508,7 +508,7 @@                                                               
             Zend_Cache::throwException(self::BACKEND_NOT_IMPLEMENTS_EXTENDED_IF);
         }
         if (!($this->_backendCapabilities['tags'])) {
-            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORT_TAG);
+            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORTS_TAG);
         }

         $ids = $this->_backend->getIdsNotMatchingTags($tags);
@@ -541,7 +541,7 @@
             Zend_Cache::throwException(self::BACKEND_NOT_IMPLEMENTS_EXTENDED_IF);
         }
         if (!($this->_backendCapabilities['tags'])) {
-            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORT_TAG);
+            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORTS_TAG);
         }

         $ids = $this->_backend->getIdsMatchingAnyTags($tags);
@@ -598,7 +598,7 @@
             Zend_Cache::throwException(self::BACKEND_NOT_IMPLEMENTS_EXTENDED_IF);
         }
         if (!($this->_backendCapabilities['tags'])) {
-            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORT_TAG);
+            Zend_Cache::throwException(self::BACKEND_NOT_SUPPORTS_TAG);
         }
         return $this->_backend->getTags();
     }