google driveのスクリプトでエラーの原因が分からない

Googleスプレッドシートで、特定のファイルを編集するたびに Script function not found: insertLastUpdated というエラーが出たという通知が来るのですが、そのファイルのスクリプトのどこにもinsertLastUpdatedという関数は使っていないため、原因が分からず困っています。
どなたか原因と解決法を分かりませんでしょうか。

通知の内容を以下に引用します。

Your script, Untitled project, has recently failed to finish
successfully. A summary of the failure(s) is shown below. To configure
the triggers for this script, or change your setting for receiving
future failure notifications, click here.

The script is used by the document MySpredsheet.

Summary: Error Message Count Script function not found:
insertLastUpdated 183

Details: Start Function Error Message Trigger End 5/6/16 1:42
AM insertLastUpdated Script function not found:
insertLastUpdated edit 5/6/16 1:42 AM
(以下時間だけ違う同じエラーが並ぶ)

スクリプトの全文を以下に引用します。

var col_airshipname = 1;
var col_voyagerlength = 3;
var col_departdate = 4;
var col_returndate = 5;
var col_hull = 7;
var col_rigg = 8;
var col_fore = 9;
var col_aft = 10;
var col_sector = 12;
var col_itemname = 13;
var col_itemhq = 14;
var col_itemqty = 15;
var col_action = 17;

function onEdit() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = SpreadsheetApp.getActiveSheet();
  var currentRow = sheet.getActiveCell().getRow();
  var currentCol = sheet.getActiveCell().getColumn();
  var sheetname = sheet.getName();
  if(sheetname == "Schedule") {
    var data = sheet.getDataRange().getValues();
    var data_airshipname = data[currentRow - 1][col_airshipname - 1];
    var data_voyagerlength = data[currentRow - 1][col_voyagerlength - 1];
    var data_departdate = data[currentRow - 1][col_departdate - 1];
    var data_returndate = data[currentRow - 1][col_returndate - 1];
    var data_hull = data[currentRow - 1][col_hull - 1];
    var data_rigg = data[currentRow - 1][col_rigg - 1];
    var data_fore = data[currentRow - 1][col_fore - 1];
    var data_aft = data[currentRow - 1][col_aft - 1];
    var data_sector = data[currentRow - 1][col_sector - 1];
    var data_itemname = data[currentRow - 1][col_itemname - 1];
    var data_itemhq = data[currentRow - 1][col_itemhq - 1];
    var data_itemqty = data[currentRow - 1][col_itemqty  - 1];
    var data_action = data[currentRow - 1][col_action - 1];
    if(currentRow > 1 && currentCol == col_action) {
      if(data_action == "◆") {
        sheet.getRange(currentRow, col_departdate).setValue(new Date());
        sheet.getRange(currentRow, col_action).setValue("");
      }
    } else if(currentRow > 1 && currentCol == col_itemqty) {
      if(data_itemqty != "") {
        var history_sheet = getHistorySheet();
        var new_row = 2;
        history_sheet.insertRowBefore(new_row);
        history_sheet.getRange(new_row, 1, 1, 15).setValues([[data_airshipname, "",  data_voyagerlength, data_departdate, data_returndate, "", data_hull, data_rigg, data_fore, data_aft, "", data_sector, data_itemname, data_itemhq, data_itemqty]]);
        sheet.getRange(currentRow, col_itemname, 1, 5).setValue("");
      }
    }
  }
}

function getScheduleSheet() {
  if (getScheduleSheet.memoSheet) { return getScheduleSheet.memoSheet; }
  getScheduleSheet.memoSheet = SpreadsheetApp.getActive().getSheetByName('Schedule');
  return getScheduleSheet.memoSheet;
}
function getHistorySheet() {
  if (getHistorySheet.memoSheet) { return getHistorySheet.memoSheet; }
  getHistorySheet.memoSheet = SpreadsheetApp.getActive().getSheetByName('History');
  return getHistorySheet.memoSheet;
}