User list number don't actualize

Hello,

I installed thousands of MU WordPress sites but this is the first time it appears

When a new member register in my MU WordPress site don't appear the number in the list.

Please see image in annex:

https://dl.dropbox.com/u/7531173/Imagem%2010.png

I'm so struggling to much,

Please help

Thank you

Vítor Maia