Access phpBB administration panel

Hello,

I followed a mini-tutorial to install phpbb-3 on my personal site to have a forum.
I downloaded it, unzipped it, renamed it, and uploaded it to my ftp.
I then deleted the install folder as instructed.

The forum works very well, at the right address.

However, the tutorial explains that I need to configure it in the administration panel.
At this stage, I am receiving an error page.

General Error
SQL ERROR [ mysql4 ]

Access denied for user '*****'@****%' to database 'phpbb' [1044]

SQL

SHOW TABLE STATUS FROM `phpbb`

BACKTRACE

FILE: includes/db/mysql.php
LINE: 174
CALL: dbal_mysql->sql_error()

FILE: includes/functions_admin.php
LINE: 2781

CALL: dbal_mysql->sql_query()

FILE: includes/acp/acp_main.php
LINE: 421

CALL: get_database_size()

FILE: includes/functions_module.php
LINE: 507

CALL: acp_main->main()

FILE: adm/index.php
LINE: 74

CALL: p_master->load_active()

I searched online for what this means, and I'm having a hard time finding it since I just started creating a site. I have already succeeded with HTML and CSS, but now with PHP... splash.

Thank you for your help!

Configuration: Windows XP Internet Explorer 7.0