my %parents_of;
my $parentid;

while ( my $line = <FFINFO> ) {
    if ($line =~ /^Folder (\d{3,5})\s+\-\s+.*\./) {
        $parentid = $1;
    }
    elsif ($line =~ /\s+subfolder\s+(\S+)\s+\-\s+.*\./) {
        push @{ $parents_of{ $1 } }, $parentid;
    }
}

sub build_path {
    my $folderid = shift @_;
    my @parents = @{ $parents_of{ $folderid } || [] };
    return @parents ? [ map {
                                map { "$_/$folderid" } @{ build_path( $_ ) }
                            } @parents ]
                    : [ $folderid ];
}

foreach my $k (sort (keys (%folders))) {
    $folderpaths{$k} = build_path($k);
    print "$k => $_\n" for @{ $folderpaths{$k} };
}

##</code><code>##

3053 => 100/3051/3053
3053 => 100/3057/3053
3053 => 100/3063/3053
3053 => 100/3066/3053