I’m trying to restore a WordPress blog from a backup. Unfortunately, all I have is an SQL dump of the database as generated by phpMyAdmin. The dump was created when the blog was running WordPress 2.9/2.9.1/2.9.2. The new blog is a brand-new installation of WordPress 3.2.1.
How can I import the contents of the SQL dump into the new WordPress installation?
I tried importing the dump into the database using phpMyAdmin before installing WordPress, but then install.php tells me that WordPress seems to be already installed and that I should delete the database tables.
If it is an older version of WP, you need to find out what version of WP generated the database, as WP upgrades the DB most times the files are upgraded and you should incrementally upgrade to also upgrade the database.
Look in the wp_options table for option 711 and see what the version is; option name will be site_transient_update_core and the value will be the download link, i.e. http://wordpress.org/wordpress-3.2.1.zip which means the version is 3.2.1
Find the version and leave a comment below.
Depending on the age of the version, you need to do manual, incremental upgrades to get to at least 3.0 where you can use auto-update.
If you import/move a DB, no need to run install.php. Just upload all WP files and folders. See Moving WordPress « WordPress Codex