On some of freshly installed servers (Debian Etch), I encountered these error messages in /var/log/munin/munin-node.log:
Use of uninitialized value in eval {block} exit at /usr/sbin/munin-node line 456, <CHILD> line 8.
What a great error message
After digging into Google results, I found it was just a problem with host_name variable in the configuration. Default value is [...]

If you encounter this warning message under Linux:
2009/03/09 21:23:19 [warn] 26827#0: 4096 worker_connections are more than open file resource limit: 1024
A solution is to use the command ulimit in nginx start script, just before lunching nginx:
[...]
ulimit  -n 65536
[...]

If like me you just have upgraded your Debian system to Lenny, you probably encounter the following warnings while launching perl:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LANG = “fr_FR.UTF-8″
    are supported and installed on your system.
perl: warning: Falling back to the standard locale [...]

Sun JRE is available in the non-free repository. You need to update your repositories configuration file (/etc/apt/sources.list).
Add the following line:
deb http://ftp.us.debian.org/debian/ etch main contrib non-free
Update apt with apt-get update command and you’re ready to install the JRE.
$ apt-get install sun-java5-jre
Check your java binary:
$ java -version
java version “1.5.0_14″
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_14-b03)
Java HotSpot(TM) [...]

apticron is a shell script that send you an email report when new packages are available on your debian server.
Install apticron
As root, do:
apt-get install apticron
apticron configuration via /etc/apticron/apticron.conf
To receive reports on your email change the EMAIL variable in the configuration file. By default, reports are sent to the root user.
EMAIL=”root” -> EMAIL=”you@domain.com”
Reports received
Now apticron will [...]