Help - Logging In dumps Warnings on established site - 5.x

Seemingly out of the blue, a site that has been up and running for over a year now throws warnings when a login is attempted. Ironically, I am trying to update the site to the latest version in the 5 series but can't login. The following verbose warnings are displayed:

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Access denied for user: 'dbo192568319@%' to database 'db192568319'\nquery: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'user', 'Session opened for <em>Tim Pascal</em>.', 0, '', 'http://www.discoverwestwood.org/user', 'http://discoverwestwood.org/user', '24.76.170.86', 1228272433) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172.', 2, '', in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Cannot modify header information - headers already sent by (output started at /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc:172) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/session.inc on line 100.', 2, '', 'http://www.discoverwestwood.org/user', 'http://discoverwestwood.org/user', '24.76.170.86', 1228272433) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'session_regenerate_id() [<a href='function.session-regenerate-id'>function.session-regenerate-id</a>]: Cannot regenerate session id - headers already sent in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/session.inc on line 103.', 2, '', 'http://www.discoverwestwood.org/user', 'http://discoverwestwood.org/user', '24.76.170.86', 1228272433) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Access denied for user: 'dbo192568319@%' to database 'db192568319'\nquery: INSERT INTO drupal5_accesslog (title, path, url, hostname, uid, sid, timer, timestamp) values('Log in', 'user', 'http://discoverwestwood.org/user', '24.76.170.86', 1, 'fde32012c130f216a231c1af99a15f57', 216, 1228272433) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172.', 2, '', 'http://www.discoverwestwood.org/user', 'http://discoverwestwood.org/user', '24.76.170.86', 1228272 in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Access denied for user: 'dbo192568319@%' to database 'db192568319'\nquery: INSERT INTO drupal5_sessions (sid, uid, cache, hostname, session, timestamp) VALUES ('fde32012c130f216a231c1af99a15f57', 1, 0, '24.76.170.86', 'messages|a:1:{s:5:\\&quot;error\\&quot;;a:4:{i:0;s:555:\\&quot;user warning: Access denied for user: &amp;#039;dbo192568319@%&amp;#039; to database &amp;#039;db192568319&amp;#039;\\nquery: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, &amp;#039;user&amp;#039;, &amp;#039;Session opened for &am in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

Warning: Access denied for user: 'dbo192568319@%' to database 'db192568319' query: INSERT INTO drupal5_watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Cannot modify header information - headers already sent by (output started at /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc:172) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/common.inc on line 314.', 2, '', 'http://www.discoverwestwood.org/user', 'http://discoverwestwood.org/user', '24.76.170.86', 1228272433) in /homepages/18/d153920459/htdocs/www/discoverwestwood/includes/database.mysql.inc on line 172

I am at a loss. I'm reluctant to just 'try stuff' for fear of making things worse. Any suggestions would be appreciated. TIA.