In order to add the .aii test, you will need to first add a Test Project to the Solution you have open. For example, I am creating a ASP.NET MVC 2 web application that I will name "NewApplication" (done through File > New > Project/Solution, then choosing ASP.NET MVC 2 web application). Before I can add any WebAii tests to the Solution, I have to have a Test Project already setup (this is what the error you provided is describing).
After creating my Solution, I click File > Add > New Project (see AddTestProject2_1.png) to bring up the new project dialog.
At the new project window (see AddTestProject2_2.png), click Test on the left column, then select Test Project. On this page you can also name the Test Project to make it more identifiable before clicking Okay). When done, click okay.
This will add the test project to your Solution. Right-Click the Test Project you just made and choose Add > Existing Item (See AddTestProject2_3.png). This will bring up a "browsing" window to allow you to select the .aii file and its' resource file (the .resx with the same name).
Navigate to the location that has both of these files (see AddTestProject2_4.png). If you do not see them listed, change the "File Type" popup to be All Files (*.*). Select both yourtest.aii and yourtest.resx (where 'yourtest' is the name of your test, (For you Chakravarthy, look for 'Add Attribute Group - General test.aii' and 'Add Attribute Group - General test.resx'). When you have them both selected, click cancel.
If you forget/neglect to select the .resx file, Visual Studio will remind you with the following message (also see screenshot):
Resource file for 'Testname' is missing. Locate the file?
If you get this message, click yes and use the browsing window to navigate to and select the file. This should allow you to add the WebAii test to your solution. Please let us know if you need further assistance doing this.
All the best,
the Telerik team