I have the same book by Goh which I would be lost without I never realised there was so much involved. Al was ging well and I was starting to think it was going to be easy then I got stuck at page 41.
I think the problem was that I was trying to use the 'Username' 'Personal Name' and 'password' from page 389 as instructed in the book. Mercury won't accept the usernames though as it wont except usernames over 16 characters long so I left off the @example.com parts of the usernames and they all added fine. I hope this helps.

Quick caution note. I am now stuck on page 45 my thunderbird email accounts added won't work keep getting mail.example server 'username or password incorrect'. Not being a PC expert I am don't know what the problem is, the lines I have followed are so far are: was it because I shortened the username in mercury (which I doubt). Or was it the Configuring Mercury on page 38.Told to Edit /MercuryMail/Mercury.INI with:

myname example.com # Canonical name for this server
and add:
example.com : example.com
But:

There are two mercury.INI files in Mercury mail with almost identical coding in.

I have tried just changing one, then just the other and then both. I still cant send an email in thunderbird from any of my test accounts to the others.

Any help anyone?

Thank you.