SAP Message R1759 - Maximum no. of role definitions (&) in this set exceeded

Diagnosis
The BP relationship category determined the maximum number of BP roledefinitions that may belong to the same BP role definition set at thesame time.
You tried to add another BP role definition to the BP role definitionset. An event within the validity period of the role definition to becreated already has more than the maximum number of relationships inone set.

System Response
Error message
You cannot create the BP role definition with this validity period.