Simple WiX Custom Action in Custom UI Ends Prematurely

Question

Using Visual Studio 2012, WiX 3.7, when I try to execute a Custom Action in my Custom UI to validate a product key input, the installer simply goes to a "Setup Wizard ended prematurely" dialog and forces you to Exit (there is no error message thrown) no matter what is entered into the product key input.

The guide I was following is http://www.schiffhauer.com/downloads/WiX-Walkthrough.pdf

I've ran the .msi with logging enabled and I still don't see what is wrong. I've included below what I think is all the pertinent information, if you want more please let me know. I'm not sure how to debug this in Visual Studio, the System.Diagnostics.Debugger.Launch(); in the CustomAction doesn't seem to do anything. I was able to get Debugging to work via http://www.davidmoore.info/2010/06/28/how-to-debug-a-windows-installer-custom-action/ but even when setting breakpoints VS just says msiexec.exe has triggered a breakpoint and Source Not Available.

UI.wxs:

<Control Id="Next" Type="PushButton" X="236" Y="243" Width="56" Height="17" Default="yes" Text="Next">
  <!-- ValidateProductID using CustomAction 'LicenseCheckAction' -->
  <Publish Event="DoAction" Value="LicenseCheckAction">1</Publish>
  <Publish Event="SpawnDialog" Value="InvalidPidDlg">PIDACCEPTED = "0"</Publish>
  <Publish Event="NewDialog" Value="InstallDirDlg">PIDACCEPTED = "1"</Publish>
</Control>
<Control Id="Cancel" Type="PushButton" X="304" Y="243" Width="56" Height="17" Cancel="yes" Text="Cancel">
  <Publish Event="SpawnDialog" Value="CancelDlg">1</Publish>
</Control>

Product.wxs:

<Binary Id="LicenseCheckDLL" SourceFile="..\LicenseCheck\bin\$(var.MyProj.Configuration)\LicenseCheck.CA.dll" />
<CustomAction Id="LicenseCheckAction" BinaryKey="LicenseCheckDLL" DllEntry="LicenseCheck" />
<UIRef Id="$(var.ProductName)_UI" />

CustomAction:

public class CustomActions
{
    [CustomAction]
    public static ActionResult LicenseCheck(Session session)
    {
        try
        {
            session.Log("Begin LicenseCheck");
            string Pid = session["PIDKEY"];
            session["PIDACCEPTED"] = Pid.StartsWith("1") ? "1" : "0";
        }
        catch (Exception ex)
        {
            session.Log("ERROR Caught in custom action: {0}", ex.ToString());
            return ActionResult.Failure;
        }
        return ActionResult.Success;
    }
}

Log:

Action 10:57:04: LicenseAgreementDlg. Dialog created
MSI (c) (A4:64) [10:57:05:863]: PROPERTY CHANGE: Adding LicenseAccepted property. Its value is '1'.
Action 10:57:06: LicenseKeyDlg. Dialog created
MSI (c) (A4:64) [10:57:07:017]: PROPERTY CHANGE: Adding PIDKEY property. Its value is '**********'.
MSI (c) (A4:64) [10:57:21:142]: PROPERTY CHANGE: Modifying PIDKEY property. Its current value is '**********'. Its new value: '**********'.
MSI (c) (A4:64) [10:57:21:215]: Doing action: LicenseCheckAction
Action 10:57:21: LicenseCheckAction. 
Action start 10:57:21: LicenseCheckAction.
MSI (c) (A4:64) [10:57:21:239]: Creating MSIHANDLE (1) of type 790542 for thread 6756
MSI (c) (A4:EC) [10:57:21:240]: Invoking remote custom action. DLL: C:\Users\dirt\AppData\Local\Temp\MSI2AEF.tmp, Entrypoint: LicenseCheck
MSI (c) (A4:58) [10:57:21:241]: Cloaking enabled.
MSI (c) (A4:58) [10:57:21:241]: Attempting to enable all disabled privileges before calling Install on Server
MSI (c) (A4:58) [10:57:21:241]: Connected to service for CA interface.
MSI (c) (A4!A4) [10:57:21:280]: Creating MSIHANDLE (2) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:280]: Closing MSIHANDLE (2) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:300]: Creating MSIHANDLE (3) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:300]: Closing MSIHANDLE (3) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:331]: Creating MSIHANDLE (4) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:333]: Closing MSIHANDLE (4) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:335]: Creating MSIHANDLE (5) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:335]: Closing MSIHANDLE (5) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:336]: Creating MSIHANDLE (6) of type 790531 for thread 9892
MSI (c) (A4!A4) [10:57:21:337]: Closing MSIHANDLE (6) of type 790531 for thread 9892
MSI (c) (A4:EC) [10:57:21:341]: Closing MSIHANDLE (1) of type 790542 for thread 6756
Action ended 10:57:21: LicenseCheckAction. Return value 3.
DEBUG: Error 2896:  Executing action LicenseCheckActionfailed.
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2896. The arguments are: LicenseCheckAction, , 
Action ended 10:57:21: WelcomeDlg. Return value 3.
MSI (c) (A4:50) [10:57:21:343]: Doing action: FatalError
Action 10:57:21: FatalError. 
Action start 10:57:21: FatalError.
Action 10:57:21: FatalError. Dialog created
Action ended 10:57:23: FatalError. Return value 2.
Action ended 10:57:23: INSTALL. Return value 3.
MSI (c) (A4:50) [10:57:23:556]: Destroying RemoteAPI object.
MSI (c) (A4:58) [10:57:23:556]: Custom Action Manager thread ending.

Answer 1

I notice that the guide doesn't mention the CustomAction.config file. Here's what I use:

<configuration>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <supportedRuntime version="v4.0.30319" />
    </startup>
</configuration>

In case you haven't found it, the documentation for this is at %ProgramFiles(x86)%\WiX Toolset v3.7\doc\DTF.chm.