I am having problem with users getting "Access Denied Error" for subsites in
Sharepoint.

I would like to allow them access to ONLY the subsite.


Here is the scenario :

There is a subsite that several users need access to.

So, I have a site called http://esportal/SiteA/M6

There is a subsite called http://SP2007/SiteA/M6/M61

I want the users to be able to go directly to http://SP2007/SiteA/M6/M61 URL and
have access, and get access denied if they go to http://esportal/SiteA/M6 .

I am assigning the users to the M61(the subsite) owner groups. But until I
put the users in as (at minimum) visitor to http://esportal/SiteA/M6 they
cannot access the subsite. They will get the "Access denied Error" . I have also
set up the subsite not to inherit master page or style sheet (not inherit from
parent) ,also removed the inheritence from the parent site.But did not resolve
the issue.

And one thing we observed is that if a user with an adminstratoive right has
logged in once in the morning to any of these sites, another user will not get
the error on the subsite for a while, even when the user with admin rights loggs
off.

Could anyone suggest what I need to do to resolve thsi problem.

When I googled I have seen that other people have posted this problen
but did not see any solution.