No, it is not possible by using Modify settings and columns. What you can do is to open the file overview.aspx in FrontPage 2003 and program that the link button Respond to this survey does not exist/is hidden after a certain date, OR, you may want to put a script in the file NewForm.aspx that will not make it possible for users to answer the poll after a certain date.
Michael Jansson
/HumanData
Michael Jansson
SharePoint Consultant + Trainer