--- tabledrag.js	2009-06-18 12:24:24.000000000 +0000
+++ tabledrag.js	2010-09-14 16:01:25.000000000 +0000
@@ -130,7 +130,7 @@
         });
         if (index > 0) {
           cell = row.children(':nth-child(' + index + ')');
-          if (cell[0].colSpan > 1) {
+          if (cell.length && (cell[0].colSpan > 1)) {
             // If this cell has a colspan, simply reduce it.
             cell[0].colSpan = cell[0].colSpan - 1;
           }