IPtables
 

So I am new to ubuntu and am trying to work with "iptables". I have ubuntu version 10.04, in the terminal I try to create a new iptable by writing:

iptables -N chain

but the response is:

FATAL: Error inserting ip_tables.........

can anyone help?

also it says "you must be root", what does root mean?

the "chain" on the end shoud be the name of the new chain. you might want to look at what is already in your iptables first with
im pretty sure all these action have to be done as root.
you can become root by typing
and entering your password.
or use sudo like this.
in the future you might want to try
or
befor posting.
most console applications/commands have build in help or man(manual) pages. There are also some great tutorials on the web about this subject.

To answer your secondary question directly:
"root" is a user defined on pretty much all UN*X systems. It is basically a "system administrator" account with permission to do just about anything. You can become "root" by doing an "su" command and typing the password. You can run programs as root by using the "sudo" command if you have permissions to run this.

EDIT: root user is very powerful. So, as a general rule, you should not run things as "root" unless you need to. Some programs, like iptables, do require you to run as root because they work directly with the core of the system.