Thank you @markkus and @jarey for your replies. I did what you suggested about re-installation and the problem persisted. I then discovered something...
...the installation manual may be outdated. The file in question on Step 7 is mongod.conf instead of mongodb.conf.
Step 7 Corrected.png
step7.png
Can @psychobunny or whoever in charge of the Doc double check this and make the proper correction?
