I point out that the trial is 2012 while the text indicates AutoCAD P & ID 2013.
You could try downloading and see the error at the following link
To answer your inquiry below regarding release of P&ID in Italian, we have no avauilable updates yet. You can always tune in to our website www.autodesk.com or if you are interested in purchasing the product in the near future, you may contact our Reseller and inquire about options that will suit your needs best.
I wanted to confirm my understanding also that what you have downloaded is 2012 version. Because I tried the link you provided and was able to download 2013.
Please let me know by responding to this message so we can fix any existing issue if any when it comes to the version listed on our website as compared to the actual product you've downloaded.