Debug a Snippet of Magento Code

We have a snippet of code that was designed to dynamically add categories to the store during the import of a CSV file. This snippet of code is located in an overridden class located in products.php. We have a test CSV load file that is loading products and variations successfully using the new [login to view URL] file, however it doesn't insert the new category information that is provided for each row of product data in the CSV. I'm looking for a Magento expert with the ability to follow the coding logic or single step through the code, basically determine why this snippet isn't working properly.