Search Tab is not working, text box is not showing up

Hi, I am using  Robohelp HTML 8 and publish project to Robohelp server 8, I using the webhelp pro to publish, then I view the project from the IE browser , everything works fine, except that, when I click on the search tab, the text box is not coming out and I am not able to type and search. I am not sure where I did wrong, anyone has any ideas? thanks