Fails to start QtWebProcess.exe if installed in a path containing spaces

Sorry, this will be a bit long winded, but it's hard to provide a short example...

I have an application that uses QtWebkit2 via QML WebView. I have bundled it with all needed dependencies and it runs fine on a fresh windows installation.

I've created an installer that copies everything to C:\Program Files\My-Company\My-App\

If I start the application from there it still runs fine, only Webkit does not work anymore. Upon application launch I get an error message like this:

Failed to start " C:/Program Files/My-Company/My-App\QtWebProcess.exe 876"

or

Failed to start " C:/Program Files/My-Company/My-App\QtWebProcess.exe 864"

The numbers vary between runs.

If I now copy the "My-Company" folder to my desktop and run it from there, everything works as expected.

My conclusion was, that it might be a permission issue of some sorts. But even giving my user full access to the installation folder does not resolve the issue.

I still think it might be a permission issue, but I have no idea what permissions are needed for QtWebProcess.exe and where/what it wants to access.