Description:
------------
Running the function db2_num_rows() with the Windows DLL returns -1. Running the same code on a SLES machine returns the correct number.

Reproduce code:
---------------
$cnx = db2_pconnect($cnx_string, '', '', array(
  'autocommit' => DB2_AUTOCOMMIT_ON,
  'DB2_ATTR_CASE' => DB2_CASE_LOWER,
  'CURSOR' => DB2_SCROLLABLE,
));
$query = "SELECT * FROM mytable";
$result = db2_exec($cnx,$query);
print "Row count: " . db2_num_rows($result) . "\n";
$count = 1;
while(db2_fetch_assoc($result))
  $count++;
print "Real row count: {$count}\n";

Expected result:
----------------
Row count: 29
Real row count: 29

Actual result:
--------------
Row count: -1
Real row count: 29