Getting this message

Error establishing a database connection

what does this mean and how can i fix it?
i am using wordpress 2.8.4 version.

It means your MySQL connection settings are incorrect. Check with your host and make sure you are using the right URL and database name to connect.

i will work on my client’s website.

he will need a wordpress upgrade 2.8.4_3.0.3

how can i be sure that everything goes ok?

they only gave me wordpress admin password.

If WP can’t connect to the db you will not be able to log into the admin section so you are going to need FTP access to change the database connection manually (unless you do a clean install). The db connection information is in the wp-config.php file in the root folder of the WP install.

i will give this job to an outsourcing person.
he wants to have access to database user information
from where can i get that?

he told me cpanel password is ok also.he will backup and upgrade to 3.0.3

the site belongs to my client i am little bit hesitant to give cpanel password.
any suggestions or recommendations?

if its upgrade from Wordpress 3.0.X to 3.0.3 it should not be a problem to use the auto installer when you are inside the WP Admin

Backup for database you could take and then allow the outsourcing person to perform the upgrade.

There are also backup plugins available which backup everything for you so that you can restore it to that point.

Cpanel passwords I agree should not be easily given out… unless known person because it gives him access to a whole host of other features too…