2489308 - DDIC_ACTIVATION phase hangs and job RDDIMPDP fails with ERROR_MESSAGE

Addon installation/upgrade or support package update hangs in phase DDIC_ACTIVATION. In SM37, it can be seen that the job RDDIMPDP fails with following log entries:

Job log overview for job:    RDDIMPDP / <JOB_NUMBER>
 Job log    Time     Message text uncoded                                        Message ID Msg.no. Msg.typ
 14.06.2017 11:43:21 Job started                                                     00       516      S
 14.06.2017 11:43:21 Step 001 started (program RDDIMPDP, variant , user ID DDIC)     00       550      S
 14.06.2017 11:43:21 Program RDDIMPDP is running in client 000                       PU       050      S
 14.06.2017 11:43:21 Background job could not be scheduled (see system log)          PU       004      E
 14.06.2017 11:43:21 Job canceled after system exception ERROR_MESSAGE               00       564      A

In SM21, following system logs can be seen:

BP_STEPLIST_EDITOR: Invalid step values (step 1) found. Reason:
EJ8 > The language with the key Z is not installed
BP_JOB_EDITOR: Job RDDMASGL is invalid. Reason:
EFT > Step 1 contains illegal values

• SAINT or SPAM

TRBAT, WARNING:       Background job RDDIMPDP could not be started or terminated abnormally., ZLOGIN_SCREEN_INFO_DEL, ACT_UPG, , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , BC-UPG-OCS-SPA , Support package tools for ABAP , Problem