管理面板中的产品类别为空

Question

I use magento API to add products to my store. the products fall in under their categories correctly in the fronted, however, when I go to the admin panel under Catalog -> Manage Category, I do not see any of the products under their categories, all the categories are empty. Categories and sub categories are showing in the Manage Category view, but the products are not showing under the categories. I tries refreshing the cache but that didn't help, any suggestions here??