In reply to jwatt_f:
The second argument to set() is not the module where the set() is being called. It is the ‘target’ instance name of where get() will be called.
In your top-level module, you should always target ‘uvm_test_top’. This is the name of the top-level class created by the run_test() call. In your test class, you should get() every item set in the top-level and place it in the required agent’s configuration object, and then pass the agent’s configuration object in the config_db, targeting the correct agent’s hierarchy.
The UVM Cookbook explains how to use the config_db correctly.