Expert Magento Developer for Trobleshooting Project

We had a Magento developer create a Magento 1.6.1 CE website for us. Everything looks fine on the front-end, but there is a major problem on the back-end. We cannot add additional product categories to the catalog. When we try to do this, we don't get confirmation that the category was created and we don't get an error message.
We are stumped why this is happening and need a Magento expert to come in and assess what the problem is and what needs to be done to fix it.

This is not for an Intermediate Magento developer. You must have a solid 3 years of Magento development experience and be an extremely good troubleshooter.

Fix this problem and we will hire you to manage the site for us and do other installations.

You must show us proof that you are a true Magento expert.

Show us that you are Magento certified and this will be a step in the right direction.