Hello!
I believe, based on the routes you say you copied the files, the commands to change the permissions are wrong.
If the blog (CMS) is installed to /opt/lampp/htdocs/buddhistblog, then that’s the path you should use:
chown -R www-data:www-data /opt/lampp/htdocs/buddhistblog
chmod -R 755 /opt/lampp/htdocs/buddhistblog
Note, however, that the user:group (for the first command), should be the same as the one on /opt/lampp/htdocs:
stat -c "%U:%G" /opt/lampp/htdocs
# Sample output
# root:root
So, if the user and group of /opt/lamp/htdocs is root:root, then the command would be:
chown -R root:root /opt/lampp/htdocs/buddhistblog