Problem Recognizing syntax in Update Join Query

Question

Trying to run the query:
UPDATE(
SELECT t1.idn,t2.idn, t1.demo_value,t2.demo_value2
FROM demo1 t1 JOIN demo2 t2 ON t1.idn = t2.idn
)set demo_value = demo_value2;
Gives an error:
ORA-00933: SQL command not properly ended
00933. 00000 - "SQL command not properly ended"
*Cause:   
*Action:
I was not able to run this in 1.5 so I tried it in 2.1.0.62. I tried the query in TOAD and it worked fine and it works ok in SQL*Plus.
The table definition is:
create table demo1
idn number,
demo_desc varchar2(100),
demo_value number
create table demo2
idn number primary key,
demo_value2 number
organization index;
insert into demo1 (idn, demo_desc,demo_value)
values (1,'test1',1);
insert into demo1 (idn, demo_desc,demo_value)
values (2,'test1',2);
insert into demo1 (idn, demo_desc,demo_value)
values (3,'test1',3);
insert into demo2 (idn,demo_value2)
values (1,5);
insert into demo2 (idn,demo_value2)
values (2,6);
insert into demo2 (idn,demo_value2)
values (3,7);
commit;

Answer 1

Right, seems to be a parser bug.
As workaround, just type a space between the UPDATE and the parenthesis next to it.
Have fun,
K.