in the upload behavior, you have bound the file name to the Server File Name binding.
this is circular logic and will not work.
the Server File Name binding is the final file name that is created when the file is uploaded.
it uses the File Name setting and and the rename if file exists settings to compute this
change the file name setting back to the default:
[FileName] paceholder so it will use the original fie name in computing the final file name that will be assigned to the Server File name.