Index: install.php
===================================================================
--- install.php	(revision 14318)
+++ install.php	(working copy)
@@ -1068,7 +1068,7 @@
 
 					// don't upgrade same version twice
 					$start_pos = $match[0][1] + strlen($match[0][0]);
-					$end_pos = array_key_exists($index + 1, $matches) ? $matches[$index + 1][0][1] : mb_strlen($sqls);
+					$end_pos = array_key_exists($index + 1, $matches) ? $matches[$index + 1][0][1] : strlen($sqls);
 					$version_sqls = substr($sqls, $start_pos, $end_pos - $start_pos);
 
 					if ($start_from_query == 0) {