With this code:

var db = google.gears.factory.create('beta.database');
db.open('cominar');
db.execute('CREATE TABLE IF NOT EXISTS Ajax (AJAX_ID INTEGER PRIMARY KEY AUTOINCREMENT , MODULE TEXT, FUNCTION TEXT, CONTENT_JSON TEXT);');
db.execute('VACUUM;'); // nettoye la DB

I'm trying to clean the database (VACUUM) the database at each initialisation but I get this error:

Uncaught Error: Database operation failed. ERROR: authorization denied DETAILS: not authorized

The database was created by me (the same page).

Thank you!