my ($subid, @children);
    while (($subid) = $children->fetchrow_array) {
        push @children, $subid;
    }
    for $subid (@children) {
        walktree ($subid);
    }

##</code><code>##

    while(my ($subid) = $children->fetchrow_array) {
        walktree($subid);
    }