the_what

Hey guys, As already mentioned above i struggle to reinstall the plane. The first time i tried It told me this: I tried again and again and it didnt worked, so I tried to delete the Citation 525 manually out of the aircraft folder. But its still the same, the aircraft isnt there anymore but the installer tells me its still there? Today I tried again, the same message as above appears, but also this message: What should I do, help please?