the following script produces no rows for mysql_list_fields.  the root user has permission to see fields in the db table on the mysql database.  This test failed identically on MySQL 3.22, and MySQL 3.23 beta:

<?

  $mysql_link = mysql_connect("localhost","root","mypassword");
  $mysql_result = mysql_list_dbs($mysql_link);

  $n = 0;
  while ($row = mysql_fetch_row($mysql_result))
     {
     print("mysql_result (list_dbs) = $mysql_result<br>");
     $n++;
     printf("Database number $n = %s<br>",$row[0]);

     $mr2 = mysql_list_fields("mysql","db",$mysql_link);
     print ("mr2=$mr2<br>");
     while ($rl = mysql_fetch_row($mr2))
       {
       $f++;
       print("Field number $f = $rl[0]<br>");
       }
     } // $row
  echo "<BR>";

  mysql_close($mysql_link);
?>

  the script put out the following.  I originally tried with multiple variables in the mysql_list_fields, but narrowed it down to a database and table I new existed:

mysql_result (list_dbs) = Resource id #2
Database number 1 = mysql
mr2=Resource id #3
mysql_result (list_dbs) = Resource id #2
Database number 2 = test
mr2=Resource id #4