Index: t3lib/cache/backend/class.t3lib_cache_backend_dbbackend.php
===================================================================
--- t3lib/cache/backend/class.t3lib_cache_backend_dbbackend.php	(revision 5385)
+++ t3lib/cache/backend/class.t3lib_cache_backend_dbbackend.php	(working copy)
@@ -168,7 +168,9 @@
 		);
 
-		foreach ($cacheEntryIdentifierRows as $cacheEntryIdentifierRow) {
-			$cacheEntryIdentifiers[$cacheEntryIdentifierRow['identifier']] = $cacheEntryIdentifierRow['identifier'];
+		if (is_array($cacheEntryIdentifierRows)) {
+			foreach ($cacheEntryIdentifierRows as $cacheEntryIdentifierRow) {
+				$cacheEntryIdentifiers[$cacheEntryIdentifierRow['identifier']] = $cacheEntryIdentifierRow['identifier'];
+			}
 		}
 
 		return $cacheEntryIdentifiers;