Since yesterday i am using jQuery and i love it. But in IE 8 i can't use the Accordion

I can click as often as i want ... nothing happens... 

Here is a port of my code 

2. <div id="navigationlinks">
3. 
   
4. <h1>nach Typ</h1>
5. <div>
6. <li>Typ A</li>
7. <li>Typ B</li>
8. </div>
9. <h1>nach Standort</h1>
10. <div>
11. <li>Stuttgart</li><li>Berlin</li><li>N&uuml;rnberg</li><li>D&uuml;sseldorf</li>
12. </div>
13. <h1>nach Zeitraum</h1>
14. <div>
15. <input type="text" size="10"name="datum" id="datum3"/> -
16. <input type="text" size="10"name="datum2" id="datum4"/>
17. <input type="submit" value=">"/>
18. <script>$( "#datum3" ).datepicker();</script>
19. <script>$( "#datum4" ).datepicker(); </script>
20. </div>
21. <script language="javascript" type="text/javascript">     $("#navigationlinks").accordion({});      </script>
22. </div>
 

What can i do?