Problem with mysql_fetch_array after first loop...

I've made a little programme that deletes expired records from database tables. The troublesome bit looks like this...

       $query = "SELECT ic FROM ic_ic WHERE date <= CURDATE()";
       $result = mysql_query($query) or die("Unable to get old campaigns because " . mysql_error());
              while ($row = mysql_fetch_array($result)){
           extract($row);
            ...delete records from tables where ic = ic
      }

It works fine for the fitst value of $ic, but on the second time around I get an error message saying that line [starting with "while..."] is not a valid MySQL resource. This really puzzles me because it works one time around, but not after that. $ic, incidentally, is a string originally generated from the timestamp (ie. getdate[0]) - could this be causing a problem? Many thanks! Jeffrey