Can i use my license in subdomain?
 

I want to ask if i can use my license in my subdomain too...
My license is leased...

For example :

I have the domain named "www.domain.com" and i use vbulletin license here...

I opened a subdomain "subdomain.domain.com"
or
I opened a directory "www.domain.com/directory"

can i use the license in three of this... ??

Depends. If the addresses lead to the same content, sure. If they lead to different content, you'd need three licenses.

I believe the rule is one install per separate forum. Meaning, if that subdomain leads to your main forum install, then you're ok. If you install vBulletin again in those other locations and they do not pull the same information from the database (as in it's a separate install of the forums which has different posts, etc), then you need another license.

One Instance = One License