From manual, this might apply to your situation :
[quote:gqqw1emt]Note that previewing with node-webkit runs node-webkit directly from the Construct 2 install directory. As a consequence, the AppFolder expression will return <install path>\exporters\html5\node-webkit\win32. If this poses a problem for you, use the following workaround: have a global string variable; if 'Is in preview' is true hard-code it to some development folder somewhere else, otherwise set it to NodeWebkit.AppFolder. Then use the global variable instead of the AppFolder expression.