Mac: "Application is not running" error when using NSAppleScript

Question

I am developing a Quick Look plugin on Mac OSX 10.10. To provide previews for our custom file formats, I need to call our mac application from the Quick Look plugin for which I have used the NSAppleScript class:

NSAppleScript *script = [[NSAppleScript alloc] initWithSource:
                                 @"\
                                 tell application \"MyApp\"\n\
                                 end tell\n\"];

The problem is that I always get a "Application is not running" message in the output window whether MyApp is running or not. I am running the QLMANAGE to debug this plugin. I even tried setting the full path of MyApp as:

tell application "\Applications\MyApp.app"

but it did not help. Does NSAppleScript object has permission to launch an application? Is this a permission issue with Quick Look plugin that a plugin cannot launch or connect to an application? Or some restrictions for qlmanage tool?