SAP Message WL402 - Workflow '&' no. & step no. &: Error in expression '&' or '&'

Diagnosis
One of the two expressions could not be evaluated.
INCLUDE NA_WF_ERROR OBJECT DOKU ID TX

Procedure
Precise information on the type of error can be found in the precedingmessage.
Correct the error and continue the interrupted workflow. If it is notpossible to make a correction, start the workflow again.
INCLUDE NA_WF-ADMINISTRATOR OBJECT DOKU ID TX