Setting up MediaWiki

[#1]

Could someone help an ignoramus!
I'm trying to setup mediawiki.
I get as far as installing it, running ccgi.username.plus.com/mediawiki/config/index.php, and get the following message;
PHP 5.2.6-1+lenny4 installed
Found database drivers for: MySQL SQLite
PHP server API is cgi-fcgi; using ugly URLs (index.php?title=Page_Title)
Have XML / Latin1-UTF-8 conversion support.
Session save path (/share/storage/01/us/username/mediawiki) appears to be valid.
PHP's memory_limit is 128M.
Couldn't find Turck MMCache, eAccelerator, APC or XCache; cannot use these for object caching.
Found GNU diff3: /usr/bin/diff3.
Found ImageMagick: /usr/bin/convert; image thumbnailing will be enabled if you enable uploads.
Found GD graphics library built-in.
Installation directory: /share/storage/01/us/username/mediawiki
Script URI path: /~username/mediawiki
Installing MediaWiki with php file extensions
Environment checked. You can install MediaWiki.
Generating configuration file...
Database type: MySQL
Loading class: DatabaseMysql
Attempting to connect to database server as username...success.
Connected to mysql 4.1.11-Debian_4sarge7-log; enabling MySQL 4.1/5.0 charset mode
Database username_pn exists
Creating tables...Query "CREATE UNIQUE INDEX user_name ON `mw_user` (user_name) " failed with error code "INDEX command denied to user 'username'@'IP address' for table 'mw_user' (humbug)".
Would some kind sole tell me where I'm going wrong.
I've managed to get Joomla running OK.
Thanks,
DW

[#2]

I set up several wikis for someone a couple of years ago, but unfortunately can't remember much of the detail.
Not sure this is relevant any longer , but I do remember an initial issue with the version of PHP. PHP5 was installed on the server (NOT plusnets), but it defaulted to using PHP4 due to many legacy installs. I had to add the following to an .htaccess file:
### enable PHP5
AddHandler application/x-httpd-php5 .php .php4 .php3 .phtml
From your setup report:
The line containing ""INDEX command denied to user" suggests you have a permissions issue with the SQL database. The user needs to have ALL priveleges assigned. Have a look at the site below (good install instructions) under the section "Adding a user to a MySQL Database Detailed Tutorial"
https://www.siteground.com/tutorials/php-mysql/mysql_database_user.htm
I ended up setting the SQL dbs up manually as the wizard route just confused me.
The mediawiki 'help' sites are actually pretty good but very disorganised. Try the URLs below as a starting point. Rather than search the sites themselves, I found it easier to search via google site specific searches using queries in the format: 

Quote

site:wikimedia.org search text

with 'search text' being whatever you're looking for - really useful for finding detail on errors.
http://meta.wikimedia.org/wiki/Help
http://www.mediawiki.org/wiki/Help:Contents
http://www.mediawiki.org/wiki/Manual:Contents
Best of luck.