ERROR: mysqlnd cannot connect to MySQL 4.1+ using old authen

[dev514]

Error on the install page:
ERROR: mysqlnd cannot connect to MySQL 4.1+ using old authentication

SHOW VARIABLES LIKE 'old_passwords' (returns TRUE)

It's a MySQL configuration issue: http://dev.mysql.com/doc/refman/5.1/en/old-client.html

When I resolve it I will edit this post with the workaround/fix.

[EDIT]
Not informative regarding the MySQL configuration I had assumed was the cause, but I changed PHP version and the error is gone.

5.2.13 (no error)
5.3.2 (error)
Note: Both CGI versions

[kamermans]

I guess 5.2.x was setup to send credentials in old password format to MySQL, but MySQL was using the new password format. I'm glad you've got it working now, thanks for the tip!