WordPress MU

The Mu got sucessfully installed but when I created a blog as a subdomain through admin, the url dont works. I mean I created http://hello.newcouponblog.com , it says page cannot be displayed. What can be the possible reason for this?

In my admin panel, it says that blog created sucessfully.

Did you follow all the steps in the readme, especially the bit about creating wildcard subdomains in Apache?

No. I tried to read it. But got confused. It was adding a "*" hostname record pointing at your
webserver in your DNS configuration tool.

I dont know how to add , please tell me steps

and thanks for reply/

The readme is actually very comprehensive for this. You need to do both the steps for Apache and DNS in the readme and they both happen in the first 30 lines of the readme.txt file.

In the <VirtualHost> section of the config file for your
host there will be a line defining the hostname. You need
to add the following if you want virtual hosts to work
properly:
"ServerAlias *.domain.tld"
Replace domain.tld with whatever your one is, and remove
the quotes.

and

DNS
===
If you want to host blogs of the form http://blog.domain.tld/ where
domain.tld is the domain name of your machine then you must add a
wildcard record to your DNS records.
This usually means adding a "*" hostname record pointing at your
webserver in your DNS configuration tool.
Matt has a more detailed explanation:
http://ma.tt/2003/10/10/wildcard-dns-and-sub-domains/

Trent

How to open that config file and how to add that * ? plz help. :((

You need to have access to your server or ask your host to do it. sometimes you can do it from your webhost controlpanel, it might be called something like "Aliases". If you can't install, you shouldn't be running WPMU. This is the easy stuff.

WU is already installed. I will try to ask my web host. I cant find aliases in my cpanel.

Otherwise you'll have to switch to using sub-directories instead of sub-domains (or move hosts)

Seconding cafespain on sub-directories. Some webhosts just can't handle sub-domains, which is why it's better to ask them first about WPMU with webhost or check out list of recommended WPMU proven hosts like:
http://mu.bloggles.info/wordpress-hosting/
http://mu.wordpress.org/forums/topic.php?id=382
Good luck.