Creating relationship between DC and R objects

Dear all,

We are implementing SAP Learning Solution at this step. Now, we want to create a relationship between DC and R objects. Therefore, we add relationship A022 and B022 in T778V as the relationship between D and R objects.

Now, after creating the relationship between DC and R objects on PP01 and saving it, "Error While Changing" will be appeared.

Now, I was wondering to know that how I can solve this issue.

Kind Regards,

Mohammad