BEGIN {
  open(STDERR, ">>E:/foo/bar.err") or die "invisible error";
  warn "$0 started ".localtime().$/;
}
..
# and then, further down
..
Config::Simple->import_from('E:/foo/foo.conf', \%c);

##</code><code>##

BEGIN {
  open(STDERR, ">>$path/bar.err") or die "invisible error";
  warn "$0 started ".localtime().$/;
}
..
# and then, further down
..
Config::Simple->import_from('$path/foo.conf', \%c);