Database connection error. Error path shows the site folder twice

I moved a site from one url to another with a domain name change. I think I followed the codex steps exactly but obviously I must not have. The index.php file in the home dir has this line

require( dirname( __FILE__ ) . '/dag/wp-blog-header.php' );

where dag is the folder where WP is installed.

The connection error looks like this:

Warning: require(/home/distlscx/public_html/dag/dag/wp-blog-header.php): failed to open stream: No such file or directory in /home/distlscx/public_html/dag/index.php on line 17

Fatal error: require(): Failed opening required ‘/home/distlscx/public_html/dag/dag/wp-blog-header.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/distlscx/public_html/dag/index.php on line 17

In the “warning”, the require path includes ../dag/dag/..
In the fatal error, the same thing is shown: ../dag/dag/..
but bot the error and warning show ..html/dag/..

Why would I be getting the double /dag/ folder? I’m really baffled and can’t seem to get this fixed.