WordPress copies a file upload 1000 times

When I try to upload a file using media uploader, the site hangs up and I have to close the session to come back to it. After that when I see the library it shows that file uploaded 500+ times(depending on the time after which you close the window while it hangs after you try to upload the file) and when I see using FTP, it has only one file there. So, what is it:

1). A spam or malicious hack on the server?
2). I tried uploading a swf file (by allowing the swf mime type), is this all because of that?

Help Appreciated.