Show notification when missing required resource data file.

MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/Apps/plClient/winmain.cpp

@@ -776,6 +776,11 @@ bool	InitClient( HWND hWnd )
 	resMgr->SetDataPath("dat");
 	hsgResMgr::Init(resMgr);
 
+	if(!plFileUtils::FileExists("resource.dat"))
+	{
+		hsMessageBox("Required file 'resource.dat' not found.", "Error", hsMessageBoxNormal);
+		return false;
+	}
 	plClientResMgr::Instance().ILoadResources("resource.dat");
 
 	gClient = TRACKED_NEW plClient;