2399324 - Error "The command 'tp' from tool 'tp' could not be executed successfully" happens in SUM

Error "The command 'tp' from tool 'tp' could not be executed successfully" happens in the upgrade phase TOOLVERSXML_FEATURES_R3LD_TP_EXTRACT in SUM.

Error message with the following pattern can be found in the log file tp_exe.out.
*********************
EXECUTING <SUM folder>/abap/exe/tp GETCAPABILITIES <SID> pf= <SUM folder>/abap/var/TOOLVERS.TPP
This is tp version <TP version> (release <TP release>, unicode enabled)
ERROR: Connect to <SID> failed (<Time stamp>, probably wrong environment).
TRACE-INFO: 1:  [     dev trc,00000]  <Time stamp>
TRACE-INFO: 2:  [     dev trc,00000]  DlLoadLib() success: dlopen("<SUM folder>/abap/exe/dboraslib.so"), hdl 0, count 1, addr 2416fa0
TRACE-INFO: 3:  [     dev trc,00000]  -->DbSlControl(con=-1,cmd=47=DBSL_CMD_IMP_FUNS_SET) -> changed=30, tagset=1
TRACE-INFO: 4:  [     dev trc,00000]  -->DbSlControl(con=-1,cmd=39=DBSL_CMD_SET_SINGLETASK)
TRACE-INFO: 5:  [     dev trc,00000]  -->DbSlControl(con=-1,cmd=10=DBSL_CMD_DBCA_PTR_GET)
TRACE-INFO: 6:  [     dev trc,00000]  -->DbSlControl(con=-1,cmd=10=DBSL_CMD_DBCA_PTR_GET)
TRACE-INFO: 7:  [dbsloci.c   ,00000]  *** ERROR => DbSlConnect(DBSL_DEFAULT_CON_INFO): invalid connect method (civ=-1)
TRACE-INFO: 8:  [     dev trc,00000]     DbSlConnect(con=-1) -> orc=0, rc=18=DBSL_ERR_CONNECT

tp returncode summary:

TOOLS: Highest return code of single steps was: 0
ERRORS: Highest tp internal error was: 0232
tp finished with return code: 232
*********************

SAP ABAP System Upgrade with SUM

SUM, TOOLVERSXML_FEATURES_R3LD_TP_EXTRACT,  DBSL_DEFAULT_CON_INFO, GETCAPABILITIES, DlLoadLib, DbSlControl, DBSL_ERR_CONNECT, 0232, 232 , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , BC-DB-DBI , DB Independent Database Interface , Problem