Wix toolset Installer Project & Bootstrapper Application Bundle

I have a wpf application, and a Wix Installer Project for my Installer, This Project creates .msi install package for my app. In the installer i also define FileType association of my application. (.fnn file type is associated with my Application) My application needs talks to to an external DLL through COM. So in my Installer project while i was creating Desktop Shortcut, i had to define WorkingDirectory="INSTALLFOLDER" , otherwise my application was not able to talk to this DLL in the right way. Now i have problem when i start my application through related FileType (.fnn). Since i could not define working directory of when started by .fnn filetype in the installer, application cannot comminicate with external DLL in the right way. Here is file association code: <ProgId Id="[login to view URL]" Description="[ProductName]" Icon="[login to view URL]" Advertise="yes"> <Extension Id="fnn" ContentType="application/fnn"> <Verb Id="open" Command="open" Argument="%1" /> <MIME Advertise="yes" ContentType="application/fnn" Default="yes" /> </Extension> Verb tag can get more parameters about Target file. Maybe setting that can fix the issue but i get errors while editing the .wxs file. i need you help to fix this issue. You can find whole working project attached. Please build Coils 1.0 Project in release mode, Then Build CoilsInstaller Project to build the .msi Thank you. Good luck.