I have recently find a solution to limit users session per connection.
Its a dll file which I have find it in RRAS official blog itself.
It sounds like there is a problem in the source and I cant get it to work.
Since I have no knowledge about Visual Studio 2005 and its my 1st time using it, I might have some mistake in compiling the source and make the DLL file and it could result in not working of my DLL file.
Anyways, here is the link: http://blogs.technet.com/rrasblog/archive/2007/12/20/steps-to-develop-a-ras-administration-dll-using-visual-studio.aspx
Also there is some more details in another blog post which is related to this issue from same blog and I am completely not understand it LOL.
Here is the link: http://blogs.technet.com/rrasblog/archive/2008/07/17/limit-one-connection-to-the-vpn-server-per-user.aspx
Now, When I finish all the steps (after 100 times checking and all goes well) and I get the DLL file and try to make it work as described in this link http://msdn2.microsoft.com/en-us/library/aa377858(VS.85).aspx
or any other way (regsvr32) I will get the error in attached picture.
Any Idea experts ?