XUpload - empty letters

[was]

From time to time we get some strange emails without any user data and files uploaded:

New file(s) uploaded using XUpload script.
Upload finished at: 2007-01-21 11:45
Total upload size: bytes
Upload Parameters
upload_id: 264498571901
js_on: 1
ref: http://www. ...
upload_password:
target_dir: /home/...
number_of_files: 0

What is the matter? I worry if it can be our customer who is trying to upload his or her file. Yet when I myself test the upload form everything is ok and I never get such ‘empty’ messages.

[PilgrimX182]

Well...you can view request in apache access log for this timestamp.
I receive email like this when open .../upload.cgi in browser.
Probably somebody trying to hack you. Check out logs for specific requests.