Help with update profile page

[eluser]Celyst[/eluser]
I'm having some problems designing the profile update page. What I want it to do is:
- User opens the "Update Profile" page. It is populated with the data retrieved from the database.
- User updates the information and submits it.
- If there are any validation errors (using form_validation library), the same page is shown with the validation errors, and the form is filled with the UPDATED data that the user entered.
- This continues until the user enters valid data, which will be saved into the database, and the user will be redirected to a success page.

Right now it's not working. I can load the initial data from the database, but when I update it and submit, I'm brought back to the same page with the old data, and not the new data that I have updated.