sendmail aliasing to local file doesn't work

[Rokas Ralys <rokas_ralys@linkarta.lt>]

I run Sendmail 8.12 (latest unstable). In aliases file
there is line like:
mail_address: /tmp/some_file

I get errors in /var/log/mail.log like this:
Sep 27 15:38:02 w2001 sm-mta[3317]: f8RDbxv5003316: to=/tmp/some_file,
ctladdr=<mail_address@mail_server.lt> (1/0), delay=00:00:02,
xdelay=00:00:00, mailer=*file*, pri=731292, dsn=5.0.0, stat=Can't create output

I tried to remove /tmp/some_file, chown daemon.daemon, chmod 666,
nothing helps...

Why does it behave in such way? Can it be because of TAB and/or SPACES
between ':' and '/' ?
I run Debian on PowerPC PReP
Linux kernel 2.2.19, Sendmail 8.12.0-4