Thank you both for your suggestions and examples.
Initially, the lines I added in
httpd.conf looked like these:
<VirtualHost *>
#
ServerName chicken.jimmy.biosci.ac.uk
DocumentRoot /var/www/html/dokuwiki/ # this is the farmer directory
#
</VirtualHost>
I had, what I thought it was, a comment next to
"DocumentRoot", which I did not include in my first post because I thought there is no need to include my
httpd.conf comments. Apache thought that this is a second argument I was trying to pass to
"DocumentRoot" and that's why it was complaining.
I will be more careful in the future when adding comments in
"httpd.conf".
My apologies for wasting your time.
Thank you