You are already checking that the put/get succeeds in the original call: 
$ftp->put($sub_log)
        or ErrorOut("put failed ", $ftp->message);

[download]
That will call ErrorOut if the put fails.
You then $ftp->quit to close the connection, and call $ftp->put after that in the if statement, which will try uploading the file again (fails because the connection is closed).

In reply to Re^3: Error Checking with Net::FTP by vlademonkey
in thread Error Checking with Net::FTP by nickfaber

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