Query question

Hi,

I've got a query which I'd like to optimize (for using indizes):

This is a working version, but it does not do exactly what I want:

------ snip -------
SELECT m.*
FROM table1 m,
table2 ms,
table3 s,
table4 l,
table5 c
WHERE m.id = 262451
AND ms.value2 = m.id
AND l.id = m.value
AND s.id = ms.slot
AND c.id = s.contestant
ORDER BY m.date ASC
------ snap -------

This version should theoretically do what I want, but it does not work (it
gives "ERROR: Relation "s" does not exist"):

------ snip -------
SELECT m.*
FROM table1 m,
table2 ms,
table3 s,
table4 l
LEFT JOIN table5 c ON s.id = ms.slot
WHERE m.id = 262451
AND ms.value2 = m.id
AND l.id = m.value
AND c.id = s.contestant
ORDER BY m.date ASC
------ snap -------

Thanks for your help.

Regards,
Bjoern