squeeze and exim4: cannot send mail, errors [SOLVED]

I'm trying to install debian 6 squeeze and exim4 as follows:

1. In linode admin: Deploy a Linux Distribution -> select Debian 6 -> boot linode and login.

2. In putty session, basic config:

root@debian:~# apt-get update

…

root@debian:~# apt-get upgrade --show-upgraded

…

Setting up acpid (1:2.0.7-1) …

Starting ACPI services….

root@debian:~# echo "playground" > /etc/hostname

root@debian:~# hostname -F /etc/hostname

root@debian:~# vi /etc/hosts

127.0.0.1 localhost.localdomain localhost

109.74.205.143 playground.alexatnet.com playground

…

3. In putty session, exim4 config, following http://library.linode.com/email/exim/se … -6-squeeze">http://library.linode.com/email/exim/send-only-mta-debian-6-squeeze

root@debian:~# apt-get install exim4-daemon-light mailutils

…

root@debian:~# dpkg-reconfigure exim4-config

typed exactly as instruction recommends, only replaced sample domains with playground.alexatnet.com and playground.

root@debian:~# echo "This is a test." | mail -s Testing alex.netkachov@gmail.com

2011-03-01 22:42:02 1Pucws-0000lJ-IJ Cannot open main log file "/var/log/exim4/mainlog": Permission denied: euid=101 egid=103

2011-03-01 22:42:02 1Pucws-0000lJ-IJ <= root@playground.alexatnet.com U=root P=local S=405

2011-03-01 22:42:02 1Pucws-0000lJ-IJ Cannot open main log file "/var/log/exim4/mainlog": Permission denied: euid=101 egid=103

exim: could not open panic log - aborting: see message(s) above

Can't send mail: sendmail process failed with error code 1

I've repeated the steps with different values in /etc/hosts, different domains in exim options (redeploy the system each time) - the same error.

Please help.

BTW, I would like to use alexatnet.com as FQDM in /etc/hosts and exim config. Is this possible?

Thanks,

Alex