SAP startup/R3trans errors on AIX/HP-UX/Unix/Linux

If R3trans -d returns:
exec(): 0509-036 Cannot load program R3trans because of the following errors:
0509-150 Dependent module libsapu16.so could not be loaded.
0509-022 Cannot load module libsapu16.so.
0509-026 System error: A file or directory in the path name does not exist.

try setting LIBPATH to /usr/sap/'<'SID’>’/SYS/exe/run on AIX or SHLIB_PATH (HP-UX) or LD_LIBRARY_PATH (other UNIX systems)

Useful Notes:
602843 – Environment settings for R/3/Oracle on UNIX

Also look at related notes below the text on this note.