Installing two wordpress blogs with same users ??

Hi,
I need to an additional wordpress blog under a sub-domain of my primary blog (symposiumz.net)
And I dont want the users to register again at the new blog.
I installed a new blog at collinfo.symposiumz.net which shares the same database with that of symposiumz.net(my primary blog)
I used both these guides but it doesn’t seem to be working or I dont know if I made anything wrong.
http://blog.dreamhosters.com/kbase/index.cgi?area=3050
http://justintadlock.com/archives/2008/09/20/installing-two-wordpress-blogs-with-the-same-users

As I try to log in to my new blog it says “You do not have sufficient permissions to log in to see this page”

I know devilsworkshop had earlier been using the same technique (Same login credentials for all its blogs) even before it came to wordpress mu.

Actually I thought of sending a mail to you rahul, but I thought it would serve many ppl if I posted here.