I've never used this corporate code, but here is the way you apply corporate codes to your account.

Log-in. Click on 'View/Edit profile' on the left. The second section allows you to enter the name of the corp and your corporate ID. Then click 'submit' at the bottom.

The next time you log-in and make a reservation, you should have a corporate rate option under the tab 'select rate'. I believe that most corporate rates are 15% off, so only an extra 5% over the AAA rate.