Fix a Duplicate Bug in a CMS

I need someone to find and fix a bug in a web php/mysql web app that I use for one of my websites. The bug for some reason causes each url on my site to have muliple duplicate pages. I need someone to fix the problem so that, the duplicate pages dissappears, or points to the original page. Like it redirects them to the original page. For example the url of my site is built like this... [login to view URL] The number's in the URL is the date in which the item was added. However, sometimes, there could be 20-100 items added in a day. I think there's where the CMS gets confused. [login to view URL] [login to view URL] [login to view URL] If I just put in a random day (even days that don't exist) in the URL, it still sends you to the same item, but the URL is incorrect. It should return a 404 or something. But for some reason, it shows the same item. This causes duplicate content penalty from [login to view URL]