[Plugin: NextGEN Gallery] remove images from cimy header rotator folder

hi guys,
yesterday i uploaded a new picture in the cimy rotator, but the system does not find it, showing me “file not found, error 404”
so the cimy rotator of the homepage is blocked with “uploading images…” in an empty white field.
i wanted to delete all images to reset it, but the system is not working in this direction.
so i am not able to manage the pictures and i don’t know where a folder is.
please help
thanks
from italy
valterpaiola.it