WordPress MU

Sorry, domain mapping only works on virtual host installs.. Why this Message. If anyone know Please Reply.

well, it means what it says: you are trying to use the domain mapping plugin with a subdirectory install isntead of a virtual host install of wpmu

I am new in WPMU and don't know how to install virtual host? Is that a option at installation step. I am using a IP address instead of any domain name and installed main WPMU into a subdirectory. I could install it properly and make few blogs. Those show properly like:

myip/subdirectory-wpmu/blog1
myip/subdirectory-wpmu/blog2
myip/subdirectory-wpmu/blog3

etc. But when i placed domain_mapping.php and sunrise.php this problem appeared. Should i use a domain name instead of dedicated IP? Is WPMU don't work on IP.

Thanks for your reply.

If you have blogs liek this:
myip/subdirectory-wpmu/blog3

Then you can't use Domain Mapping plugin. Blog must be like:
blog3.myip/subdirectory-wpmu/

Use Multi Site manager instead OR reinstall and choose the subdomain option on the install screen.