I am using a simple open source download store script to sell ebooks. The script is simple and works well except for one problem. When I try to add a new product, I often get an error saying I'm uploading a duplicate listing when it's the first time I've uploaded it. I need to find the cause of this error. I really don't care if I accidentally upload a duplicate item. Under normal circumstances, when I upload a new ebook, the script renames my original file with a very long string of letters and numbers, one for the file name and a different long file name for the demo file (a "preview" file like a jpeg or pdf). It puts the file in a "dl" folder and the demo/preview file goes into the "demo" folder. The script uses a MySQL database, which I created in cpanel. Perhaps it's a problem in the database? This should be a simple fix for an experienced php person. I have almost no budget and can't afford much. My small site is making no money yet.