Fun query help

[eluser]WanWizard[/eluser]
To work with transactions, you need a database (or table) that is transaction aware. For MySQL installations, that means you have to use InnoDB instead of MyISAM to create your tables.
The database library has methods to support transactions, commits and rollbacks.

As to your query: PHP is case sensitive, so $_POST is not the same as $_Post. So $_POST['balance'] does not exist when you call the insert method.

And to even further your skills: spend some time reading through the manual. Well worth the time. Then you'll learn never to use $_POST, but to use the form_validation library to validate and sanitize your form variables.