WordPress MU

Getting this error when click any link in my main blog
Fatal Error
Could Not Find Blog!
Searched for cairo.invisioneyes.com/about/ in cairo_mu::wp_blogs table. Is that right?
Please check that your database contains the following tables:

* wp_blogs
* wp_users
* wp_usermeta
* wp_site
* wp_sitemeta
* wp_sitecategories

If you suspect a problem please report it to support forums!

==============
Another problem i am working under a subdomain because i did not buy a domain yet so when any one register and click the activation link it say him can not find in server error

Any Help

"Another problem i am working under a subdomain because i did not buy a domain yet so when any one register and click the activation link it say him can not find in server error"

That's probably the whole cause of almost all your problems.

Okay.. I had the same problem while using Non-Vhost options. Under this type of installation the root directory cannot have a blog, for some odd reason it just doens't work right now.