Problem with server-side filtering using sieve

[nunatarsuaq]

Hello to everybody

I'm a new user here and found this list while searching for solution
to my problem.

I have a running mail server with postfix and cyrus-imap and would
like to start filtering incoming messages on the server side.
I tried to put a filter using sieve shell according to this tutorial
http://wiki.linuxwall.info/doku.php/en:ressources:astuces:sieve but
with no results.

Here's my configuration:

I created a file with a sieve filter:

if header :contains "X-Spam-Flag" "YES" {
 fileinto "Junk";
 stop;
}

I tried also type fileinto as "user.USERNAME.Junk",
"user/USERNAME.Junk" and "user/USERNAME/Junk")

Now when I invoke

# sieveshell -u cyrus -a cyrus localhost (tried also with a user other
than cyrus)

and type

> put sieve_filter

I get an error:

upload failed: put script: script errors:
line 2: fileinto not required


What does it really mean?
What can be done to get it working?

Rangifer