3211526 - Error "The index list could not be created" in SUM phase MAIN_SHDCRE/JOB_RDDINDPR

When upgrading SAP ERP 6.0 to ERP 6.0 EHP8, there is following error in SUM phase MAIN_SHDCRE/JOB_RDDINDPR.

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Checks after phase MAIN_SHDCRE/JOB_RDDINDPR were negative!

Last error code set:
Single errors (code <= 8) found in logfile 'PHASE_JOB.ELG'

*ERROR* :
Batchjob RDDINDPR failed.
The following errors were detected in the log files:

# Find the detailed information in log 'INDPRP.SSP':
4 ETG037 Report name ...: "RDDINDPR"
4 ETG011 " "
4 ETG011 "Parameter MULTI_TENANCY = ''"
4 ETG011 " "
4 ETG011 "Start subroutine DUMP_KNOWN_INDEXES"
4 ETG506 Copying index list to file "<upgrade directory>/var/OLDIND.IND"
2EETG507 The index list could not be created (error code = "8").

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Write permission is available for user <sid>adm on "<upgrade directory>/var". However, file "OLDIND.IND" cannot be created and does not exist under this directory.

SAP ERP 6.0

"SUM",  "The index list could not be created", "MAIN_SHDCRE/JOB_RDDINDPR", "JOB_RDDINDPR", "Copying index list to file", "var/OLDIND.IND", "OLDIND.IND" , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem