3431550 - Error LIBPATH is set to <not set> in PREP_EXTENSION/TOOLCHECK_SPAM while doing upgrade

While running SUM in phase PREP_EXTENSION/TOOLCHECK_SPAM while doing upgrade

servername:{SID}adm 12> /usr/sap/{SID}/SYS/exe/uc/rs6000_64/sybctrl version
 
NLSUI_INIT_TRACE_LEVEL set to 'high'                                           
 
loadIcuDo() is called                                                           

Program is compiled with ICU version 50.1                                      

Required ICU library files: libicuuc50.a libicudata50.a libicui18n50.a          
 
Searching for libicuuc in environment path LIBPATH                              

LIBPATH is set to <not set>                                                     

Could not open ICU shared library libicuuc50.a                                 

Error message: "        0509-022 Cannot load module .
        0509-026 System error: A file or directory in the path name does not exist." 

Searching for libicuuc in additional path /usr/sap/{SID}/SYS/exe/uc/rs6000_64     

SAP Adaptive Server Enterprise 16

KBA , BC-DB-SYB , Business Suite on Adaptive Server Enterprise , Problem