The image upload.php script not working

I have the editor running but have a problem with the image upload.php script. When I try to upload a image I keep getting the error message
"/home/httpd/docs/Home/upload/Error : File exists, can't overwrite it"

This directory is empty and I think the upload.php script is not getting the filename, so it is checking a Null value.

is there a setting in php I am missing for this script?
Could do with a bit of help
Cheers
Kw