What you are describing does not seem to be a part of WP default functionality, so I took a look at your code, and it seems you are using the plugin wp-e-commerce for your store. Also, the fact that it stopped working after a WP core update seems to confirm this.
On the WP Plugin Directory, a special procedure for updating the plugin is described under the "Installation" tab. Have you followed it?
Before updating please make a backup of your existing files and database. Just in case. After upgrading from earlier versions look for link "Update Store". This will update your database structure to work with new version.
Evidently, you are not the only person who is having problems with this plugin, since 9 people out of 21 are claiming that the latest plugin version (126.96.36.199) does not work with WP 3.2.1. If the update procedure does not work, you should try to contact the author of the plugin.