open(FFINFO,"$folderfolder_file") or die "Can't open $folderfolder_file: $!\n";
# This reads in every line from FFINFO
my @subfolders = <FFINFO>;

my %parents_of;
my $parentid;

# This loop also wants to read every line,
# but the handle is already at EOF,
# so it gets nothing.
while ( my $line = <FFINFO> ) {