Check to make sure that you have created a directory called
/var/www/html/moodledata
If you haven't you need to run the following 2 lines to first create the directory and then give apache permission to read/write. (If the folder does exist, just run the 2nd line to give apache the required permissions)
mkdir /var/www/html/moodledata
chown -R apache:apache /var/www/html/moodledata