Unable to create web application in sharepoint

Hi all, I have deployed sharepoint 2007 and run sharepoint product and technologyies Configuratioin wizard, every this was done successfully. Now the problem that i am facing is I am not able to create web application.
Actually when I navigate to Create or Extend Web Application-->Create New Web Application and fill all the mendatory fields, OK, and Cancel buttons are not working.
any Idea what is the issue?