This script should be referenced with a METHOD of POST.
If you don't understand this, see this <A HREF="http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/fill-out-forms/overview.html">forms overview</A>.
<P>What could have happened is that you just reloaded this page rather than redoing the search.
<P>If you use NETSCAPE it has a tendency to try to reload a page when you go back to it.  This may be why you have this error.