Service Request Error with Multilevel Categorization

Hi CRM Gurus,

I'm receiving an error message when I fill diferent categorization levels (randomly) in a Service Request Form.

The Error is the follow:

Diagnosis

The system tries to access a specific partner function type. But in the partner determination procedure (of that transaction type/item type), no partner function of that type is defined. So the system cannot decide which partner function to take.

System Response

An error message is raised.

Procedure

Enhance the partner determination procedure

The question is what is the relation between the categorization Schema and the partner determination procedure? Because I dont remember have done any cuastomizing related to that.

Thanks in advance,