WebDynpro Application not workin for some users

I Had developed a WebDynpro Application which takes user id as input and displays some output.

Its working fine withe all users, except for one user.

Even for this user the initial screen is displaying fine, but when he submits this screen the Output is not shown it simply shows blank and the status bar of the browser shows done.

What might be the problem for it as all the permissions are same for all.

Mr.Chowdary