[Plugin: Email Log] problems

I tried posting here: https://sudarmuthu.com/wordpress/email-log

but all I get is this error:

Warning: mysql_real_escape_string() expects parameter 1 to be string, array given in /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/wp-db.php on line 450

Warning: Cannot modify header information - headers already sent by (output started at /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/wp-db.php:450) in /home/sudar/public_html/sudarmuthu.com/public/wp/wp-comments-post.php on line 82

Warning: Cannot modify header information - headers already sent by (output started at /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/wp-db.php:450) in /home/sudar/public_html/sudarmuthu.com/public/wp/wp-comments-post.php on line 83

Warning: Cannot modify header information - headers already sent by (output started at /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/wp-db.php:450) in /home/sudar/public_html/sudarmuthu.com/public/wp/wp-comments-post.php on line 84

Warning: Cannot modify header information - headers already sent by (output started at /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/wp-db.php:450) in /home/sudar/public_html/sudarmuthu.com/public/wp/wp-includes/pluggable.php on line 865

what I wanted to post there is this:

the instructions seem wrong to me. dropping a folder into mu-plugins usually does nothing…

if I only activate it for the main blog, will I see all emails that have been sent on the whole wpmu installation?

https://www.ads-software.com/extend/plugins/email-log/