So after solving this problem for the 2nd time I figured I should post my solution here!

I'm using Zen 1.3.9d, with stock_by_attributes4.7 and dynamic_drop_downs_for_stock_by_attributes_1-3-4. The problem I found was with the entry in the "includes/database_tables.php" file. The instructions left out the "DB_PREFIX" part. You should add as shown below:

define('TABLE_PRODUCTS_STOCK', DB_PREFIX . 'products_with_attributes_stock');

Worked for me, hope this helps someone else out!

Pete