No basic dates exist. Forecast dates for & not possible

What causes this issue?

You can maintain forecast dates for the WBS only after you have main-
tained the basic dates.

System Response

INCLUDE 'NA_ALLG_NOVERARBEITUNG' OBJECT DOKU ID TX

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Enter the basic dates.

Error message extract from SAP system. Copyright SAP SE.