Dear Hamidullah,
The error message is for the inactivity of the page i.e. you are logged in as admin and there is no activity for a certain time and after then you click on any update/add button. Then it will show this Page Expaired error. The Page Expaired for your website security. If you forgot to logout then the page will expair autometically after a certain time for the inactivity of the page.
Please check the issue carefully and let us know.
Best Regards,
ThemeLooks Support Team