Autocomit off in psql don't work

SuSE Linux 8.2 (i586)
PostgreSQL REL7_4_STABLE (cvs), 7.4
compiled with:
gcc (GCC) 3.3 20030226 (prerelease) (SuSE Linux)
flex version 2.5.4
bison (GNU Bison) 1.875
PostgreSQL config.status 7.4
configured by ./configure, generated by GNU Autoconf 2.53,
with options "'--prefix=/opt/pgsql' '--enable-integer-datetimes'
'--enable-thread-safety' '--disable-largefile' '--with-java'
'--with-pam' '--with-openss' '--with-gnu-ld'"

To repeat:

$ /opt/pgsql/bin/psql
Welcome to psql 7.4, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help on internal slash commands
\g or terminate with semicolon to execute query
\q to quit

olleg=# \set
VERSION = 'PostgreSQL 7.4 on i686-pc-linux-gnu, compiled by GCC gcc
(GCC) 3.3 20030226 (prerelease) (SuSE Linux)'
AUTOCOMMIT = 'on'
VERBOSITY = 'default'
DBNAME = 'olleg'
USER = 'olleg'
PORT = '5432'
ENCODING = 'KOI8'
PROMPT1 = '%/%R%# '
PROMPT2 = '%/%R%# '
PROMPT3 = '>> '
HISTSIZE = '500'
olleg=# \set AUTOCOMMIT OFF
olleg=# \set
VERSION = 'PostgreSQL 7.4 on i686-pc-linux-gnu, compiled by GCC gcc
(GCC) 3.3 20030226 (prerelease) (SuSE Linux)'
AUTOCOMMIT = 'OFF'
VERBOSITY = 'default'
DBNAME = 'olleg'
USER = 'olleg'
PORT = '5432'
ENCODING = 'KOI8'
PROMPT1 = '%/%R%# '
PROMPT2 = '%/%R%# '
PROMPT3 = '>> '
HISTSIZE = '500'
olleg=# begin;
BEGIN
olleg=# select now();
now
-------------------------------
2003-11-28 18:15:59.063438+03
(1 row)

olleg=# select now();
now
-------------------------------
2003-11-28 18:15:59.063438+03
(1 row)
olleg=# commit;
COMMIT
olleg=# select now();
now
-------------------------------
2003-11-28 18:16:42.484651+03
(1 row)

olleg=# select now();
now
-------------------------------
2003-11-28 18:16:43.085406+03
(1 row)
olleg=# commit;
WARNING: there is no transaction in progress
COMMIT

--
Olleg