blank header

hi, i spent the whole day trying to figure out how to upload a header.
the errors i encounter are:

when uploading a header, during the ” cropping time ” , it gives me a broken image link. and when i try to view that, it gives me a 404.

so i thought screw that. ill just try my luck on the “background”
when i upload the file, it said ” success ” but when i try to view the site. it is empty.

i dunno what else to do.
it would be easy if there’s like a folder where i can manually throw the files in via ftp…

sigh..

please help