The output of a command enclosed in backticks (or qx()) is not printed, it's returned. So $result contains the output of your load_data_to_db.pl. If you wanted the output to go to the screen, you need to either print $result or use system() instead of backticks.

If you have some reason other than the lack of output for claiming the command failed, you need to say that. But, as presented, I wouldn't expect that command to output to the terminal.