To install anything, you must be root. Root is the highest level of power in a Unix system. To temporarily gain root, type "su" into the command line. You will then be asked to type in your root password.
If you never entered a root password (e.g., Ubuntu), then you may have to do it slightly different.
Type "sudo su", and then you will be asked for another password. Type in your regular login password, and hit return. This should then return a root prompt.
Once you have root privaliges, you can then install the printer driver.
EDIT: Type "exit" to get out of the root enviroment.
In suse it is poiible to login to the graphical environment as root too - try it but if you get "the system administratr is not allowed to login from this screen" you need to select "allow root loggin" in the appropriate module of yast
I have tried the shell box with the commmand with "sudo su" and the password comes up ,but cannot insert any text
You are typing in text -- you just can't see it. This is Linux's way of preventing someone looking over you shoulder from seeing your password. Similar to the way you see asteriks when you type your password into a GUI.