Re-Login required after url

Hello,

I created a course and I use url to html files with dynamic PHP content. All url is displayed in a pop-up window. When I close this pop-up window and I want to continue, I have to re-login. I would appreciate any help here, since in IExloper 9, Firefox, and Chrome, I have the same issue.

Thank you very much for your help.

Best,

Daniel