Word Press MU 2.6 Site Admin Tab bug?

I just install the 2.6 release of MU and have found a bug or something in it.

Whenever I set up the new version to handle user registration and Blog creation my site admin tab in my CP disappears.

I thought I was going crazy until I reinstalled the package four times to get the same effect.

What gives and where is the OLD package, version 1.5.xx, that this function works in?

thanks –

H