Web3.js event watch problem

web3_filter.js

  // if 2nd arg is 'latest', everything is fine
  var event = book.NewRecord(null, 'latest');
  //event.get(function(err, results) {
  //  console.log(results);
  //});
  event.watch(function(err, result) {
    if(err) {
      console.log("error:", err);
    } else {
      console.log(result);
    }
  });

 
 
  // if 2nd arg is {fromBlock: 0, ...}, I get infinite errors on line#23:
  // error: Error: Can only serialize integers(...)
  var event = book.NewRecord(null, {fromBlock: 0, toBlock: 'latest'});
  //event.get(function(err, results) {
  //  console.log(results);
  //});
  event.watch(function(err, result) {
    if(err) {
      console.log("error:", err);
    } else {
      console.log(result);
    }
  });