SAP Message WL444 - Workflow:&4 Work item:&2 Activity:&3 invalid

Diagnosis
Activity number &V3& in workflow &V2& could not be started as aninvalid task is specified in the relevant workflow definition: '&V4&'.
INCLUDE NA_WF_ERROR OBJECT DOKU ID TX

Procedure
Check and correct the relevant workflow definition:
Make sure a correct task is entered for activity &V3&. To do this, usethe F4 possible entries option.