SAP Message WTY811 - Error: conversion of temporary object no. to concrete object no. equi.

Diagnosis
The object number of the equipment is not known.

Procedure
Please implement BADI EQUI_UPDATE with the function module call:
CALL FUNCTION 'WTY20_OBJNR_SET'
EXPORTING
iv_objnr = i_data_equi-itob-objnr.