New Post: Simple .Net Bootstrapper

Hi there, I've been trying for quite some time to get a simple .Net-Bootstrapper to work.
The Bootstrapper should determine if .Net 4.5 is installed and install it in case it's not installed yet and then install my product. My product installer has a custom WPF-UI.
To properly determine the .Net version I need to evaluate a specific registry key:
using (var key = Registry.LocalMachine.OpenSubKey("SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\"))
{

if (key == null)
{
    return false;
}
int releaseKey = Convert.ToInt32(key.GetValue("Release"));
return releaseKey >= 378389;

}

So I want to check the registry (in a custom action I guess), execute the .Net 4.5 web installer (http://go.microsoft.com/fwlink/?LinkId=397707) which I downloaded as an exe-file, in case .Net 4.5 is not present on the target machine and then run my product installer.
The sample code doesn't help enough. i tried it with the "Simplified Bootstrapper" but keep getting "No CA or UI entry points found in module". I'd be very gratefull if you could point me in the right direction or provde a link with an exmaple.