Hello,
SAP Notes 1493434 und 39439 helped
I resolved the issue with updateing the Xuser:
xuser -U c_J2EE -u Control,<password> -d <database_name> -n <databaseserver> -S SAPR3 set
Then test with: dbmcli -d <database_name> -U c_J2EE
Is successful the command-prompt of dbmcli will show.
Thereafter the upadate with SUM was successfully terminated.
Regards
Uwe