Popup when bought (own fault)

I think I did soemthing wrong and need some help. We have activated the popup setting that shows the decission for the user to go to checkout or stay at the current shop site. Today I tested again (after several changes yesterday) and the information field is empty (in IE you see 'could not load' message). I know that this bug is a result of one of my recent changes but I don't know where to look at. Could you please give me a hint and maybe a link to the original file of the current version?

Problem solved. I had overwritten one of the files with a 1.4.5 version. It's corrected now and works again.