--- C:/WebSites/Mantisbt/library/adodb/datadict/datadict-mssqlnative.inc.origin.php	sam.  2 févr. 2013, 20:59:00
+++ C:/WebSites/Mantisbt/library/adodb/datadict/datadict-mssqlnative.inc.patched.php	sam.  2 févr. 2013, 20:59:30
@@ -189,8 +189,10 @@
 			$rs = $this->connection->Execute( "select name from sys.default_constraints WHERE object_name(parent_object_id) = '" . $tabname ."' AND col_name(parent_object_id, parent_column_id) = '" . $v . "'");
 			if ( is_object($rs) ) {
 				$row = $rs->FetchRow();
-				$constraintname = $row[0];
-				$sql[] = 'ALTER TABLE '.$tabname.' DROP CONSTRAINT '. $constraintname;
+				if ($row) {
+					$constraintname = $row[0];
+					$sql[] = 'ALTER TABLE '.$tabname.' DROP CONSTRAINT '. $constraintname;
+				}
 			}
 		
 			$f[] = "\n$this->dropCol ".$this->NameQuote($v);