In the package, the postinstall command specified is:
/usr/bin/chmod 700 /opt/nimsoft/bin/pu
So on your AIX system, check the paths for the chmod command and pu, and is the nimsoft installation path the same as well? -> /opt/nimsoft/bin
You may need to add a new section, e.g., pu_command_AIX and then ftp the pu binary over from the AIX machine and then with 'Files' Tab selected, rt-click and add the pu binary, (since it's not java), into the package under that section, then also enter the appropriate post-installation command with the absolute paths, for that section.
Then test it again.