Im facing strange problem and its my first time to face such problem

I upgraded site from 6.2.5 to 7.0.5 and everything was smooth but after i logged as host when i click on "add new module" or "edit this page" i get popup window asking for username and password for my site as image below

http://trainingegypt.com/error.jpg

i checked the hosting control panel and made sure that there's write permission and so on, hope anyone can advise how to solve this issue