Wix - Unable to launch external exe upon building in jenkins - visual-studio-2012

Question

I am facing a strange issue. I have build the wix installer and when the setup is complete an external exe (MyEx.exe) is launched. This works absolutely fine in my local machine.
I use VS 2012 to Build.
Below is the piece of code
<Publish Dialog="MyExitDialog" Control="Finish" Event="EndDialog" Value="Return" Order="999">1</Publish>
<Publish Dialog="MyExitDialog" Control="Finish" Order="1" Event="DoAction" Value="LaunchApplication">LAUNCHAPPONEXIT and NOT Installed</Publish>
MyExitDialog.wxs file
<?xml version="1.0"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Fragment>
<UI>
<Dialog Id="MyExitDialog" Width="370" Height="270" Title="[ProductName]" NoMinimize="yes">
<Control Id="Finish" Type="PushButton" X="236" Y="243" Width="56" Height="17" Default="yes" Cancel="yes" Text="!(loc.WixUIFinish)" />
<Control Id="Cancel" Type="PushButton" X="304" Y="243" Width="56" Height="17" Disabled="yes" Text="!(loc.WixUICancel)" />
<Control Id="Bitmap" Type="Bitmap" X="0" Y="0" Width="370" Height="234" TabSkip="no" Text="!(loc.ExitDialogBitmap)" />
<Control Id="Back" Type="PushButton" X="180" Y="243" Width="56" Height="17" Disabled="yes" Text="!(loc.WixUIBack)" />
<Control Id="BottomLine" Type="Line" X="0" Y="234" Width="370" Height="0" />
<Control Id="Description" Type="Text" X="135" Y="70" Width="220" Height="20" Transparent="yes" NoPrefix="yes" Text="!(loc.ExitDialogDescription)" />
<Control Id="Title" Type="Text" X="135" Y="20" Width="220" Height="60" Transparent="yes" NoPrefix="yes" Text="!(loc.ExitDialogTitle)" />
<Control Id="LaunchCheckBox" Type="CheckBox" X="10" Y="243" Width="170" Height="17" Property="LAUNCHAPPONEXIT" Hidden="yes" CheckBoxValue="1" Text="Launch NetappAgent Configuration">
<Condition Action="show">NOT Installed</Condition>
</Control>
</Dialog>
<InstallUISequence>
<Show Dialog="MyExitDialog" OnExit="success" />
</InstallUISequence>
<AdminUISequence>
<Show Dialog="MyExitDialog" OnExit="success" />
</AdminUISequence>
</UI>
</Fragment>
</Wix>
and MyMainFile.wxs
<Condition Message="!(loc.InstallationPrivMessage)">Privileged</Condition>
<Property Id="WixShellExecTarget" Value="$(var.SourceDir)\MyExe.exe" />
<CustomAction Id="LaunchApplication" BinaryKey="WixCA" DllEntry="WixShellExec"/>.
Issue is when the same piece of code is uploaded on a Jenkins Machine. Build is successful but external exe (MyExe.exe) does not launch when I click finish at the end.
I use MSBuild v4.0.30319 and Ant 1.9.0.
I am not sure where should I start debugging. Any help will be appreciated.
Update:
Upon further investigation, I came to know that $(var.SourceDir)\MyExe.exe could be culprit. I think is valid on compile not on the build time.
I have also tried using [#MyExe.exe] but even that not worked.
MSI (c) (EC:68) [16:56:37:679]: Doing action: MyExitDialog
Action 16:56:37: MyExitDialog.
Action start 16:56:37: MyExitDialog.
Action 16:56:37: MyExitDialog. Dialog created
MSI (c) (EC:70) [16:56:48:138]: Doing action: LaunchApplication
Action 16:56:48: LaunchApplication.
Action start 16:56:48: LaunchApplication.
MSI (c) (EC:10) [16:56:48:153]: Invoking remote custom action. DLL: C:\Users\ssachin\AppData\Local\Temp\MSIF5F.tmp, Entrypoint: WixShellExec
MSI (c) (EC!B0) [16:56:48:191]: Note: 1: 2715 2: MyExe.exe
MSI (c) (EC!B0) [16:56:48:191]: Note: 1: 2715 2: MyExe.exe
Action ended 16:56:48: LaunchApplication. Return value 3.
DEBUG: Error 2896: Executing action LaunchApplication failed.
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: LaunchApplication, ,
Action ended 16:56:48: MyExitDialog. Return value 3.
Action ended 16:56:48: INSTALL. Return value 1.
MSI (c) (EC:68) [16:56:48:196]: Destroying RemoteAPI object.
MSI (c) (EC:54) [16:56:48:197]: Custom Action Manager thread ending.

Answer 1

How do you know that it is not launched? Are you sure that it is not launched, or maybe you simply can't see it? Jenkins runs in it's own session. Anything spawned by Jenkins will therefore run in it's own session as well, not visible to logged in user session.
Read my answer here on tips how to make Jenkins trigger an .exe to be visible to user session: Open Excel on Jenkins CI