Wrong Counts for child forum ?

[tisaigon]

Hello,
Our forum, www.benhvienoto.vn , is using Vbb version 4.1.0 and we are facing with the below problem:

If we have the forum tree as shown below
Category 1
- Forum1
- - forum1a
- - forum1b
- Forum2

Then the post and thread counts for Forum1 will only include posts in Forum1, and not those in forum1a and forum1b.

Please see the captured picture @ the following link to understand the problem more clearly

https://lh5.googleusercontent.com/_Oe5gQIKdsxI/TU5U5GkWeTI/AAAAAAAAA9M/W4QUuec8GjM/s1280/wrong%20count.png

Could you please suggest us how to display and count the number of posts correctly? For instant, coresponding to the example above,

counts for Forum 1 must be = Counts Forum 1a + Counts Forum 1b + Counts posts in Forum 1

Please help us as soon as you can.
We are looking forward to seeing your reply soon.

Best regards,