Hey guys...Confused with app loader

Im Running apploader trying to reinstall a "2 red flash wont turn on" blackberry...i believe its the curver 9330 its the one not with the trackball but track pad i guess...anyway...when i go to apploader and i get to the com1-unknown pin screen...everytime i connect to unknown pin it gives me the "usb unable to connect" screen...im very quick with clicking next so idk if im just not fast enough..or if its something else...sometimes i can even open up apploader and the unknown pin in the communication window will still be there and when i click next it gives me the same "usb unable to connect to this device" screen..any help is appreciated