DELETE TABLE xx do not erase index file after a vacuum full ?

Bug or problem with PostgreSQL ?

                            version
---------------------------------------------------------------
 PostgreSQL 7.4.3 on i686-pc-linux-gnu, compiled by GCC 2.95.4

select * from my_table;
   id             |   login    | passwd  | state |      email
--------------+-----------+------------+-------+------------------
(0 rows)

I had before about 800 000 lines inside ...

I have done a :
DELETE from my_table;

Now If I look at the data/bases/ folder I see that I still have a 35 Mb file
for one of the index of this table ... ???

VACUUM FULL VERBOSE ANALYSE; have been done on this table before, but I still
have for this index this message :

INFO:  index "email_my_table_key" now contains 2 row versions in 4313 pages
DETAIL:  0 index row versions were removed.
4309 index pages have been deleted, 4309 are currently reusable.
CPU 0.01s/0.01u sec elapsed 0.02 sec.

What happend ? Why the index file is still here ?

Thanks for your help !
--
Hervé Piedvache

Elma Ingénierie Informatique
6 rue du Faubourg Saint-Honoré
F-75008 - Paris - France
Pho. 33-144949901
Fax. 33-144949902