If the bad path is passed, I get exception indicating error regarding path. I can open the path in windows explorer, so clearly this option is out. I will confirm with the person who made this dll, regarding error handling in dll.
Also is there any way that I can uninstall this "LabVIEW Runtime 2015 SP1 f7" as it's not getting shown in control panel. I tried using uninstall exe for labview but it opens same dialogue box as control panel for uninstall, which does not contain LVRT 2015.