Uncaught TypeError: must start with number, buffer, array or string

I've created a little script with sql.js documentation, but i'm unable to write buffer into a.db (Win)
console gives me error: "Uncaught TypeError: must start with number, buffer, array or string"
is that something regarding "var data = db.export();" function or is there something wrong in my code?

var fs = require("fs");
var remote = require('remote');
var SQL = remote.require('sql.js');
var file = "a.db"
var exists = fs.existsSync(file);

if(!exists) {
console.log("DB creation: "+file+ "");
fs.openSync(file, "w");
}

var filebuffer = fs.readFileSync(file);

// Load the db
var db = new SQL.Database(filebuffer);
// Run a query without reading the results
db.run("CREATE TABLE test (col1, col2);");
// Insert two rows: (1,111) and (2,222)
db.run("INSERT INTO test VALUES (?,?), (?,?)", [1,111,2,222]);

var data = db.export();
var buffer = new Buffer(data);
fs.writeFileSync(file, buffer);

Start with the shown JavaScript script, focusing on the SQL.Database input and the conversion of db.export() before fs.writeFileSync. Reproduce the TypeError on Windows and verify that the script can create, write, and reopen a.db without the error.