You are working with networks and WBS elements.

One of the statements that applies to working with networks and WBS elements is that you have to maintain a network profile in the project profile. A network profile is a parameter that defines the basic properties of a network, such as its order type, number range, and scheduling parameters. A project profile is a parameter that defines the basic properties of a project, such as its project type, number range, and budget profile. You have to assign a network profile to a project profile in order to create networks within a project. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html