Could you please first confirm that you are able to execute the following command without using the bat file:
ArtOfTest.Runner.exe list="D:\Telerik Demo\TestLists\b. Add User, Create Library and folder.aiilist"
If that fails executing I'll blame the name of the test list you are using.
After you verify you are able to execute your test list with the artoftest.runner.exe in the cmd you can add the Path to Environment Variables as shown in this article. This way you will eliminate the need of navigation to in your bat file:
cd "C:\Program Files (x86)\Telerik\Test Studio\Bin"
When this is done your next step will be to create your bat file containing the following command:
call ArtOfTest.Runner.exe list="D:\Telerik Demo\TestLists\b. Add User, Create Library and folder.aiilist"
Hope this helps.