krileon wrote: Please ensure the name and formatname fields are on a public and published tab. Tab access determines field access, which will affect substitutions.

I changed fieldname on code, then worked! Thank you!
How I can show poster's name who is anonymas user. Is there substitutions to show these name?

krileon wrote: Well you can use an IF check to see if their user_id is 0 and then put "Anonymous" or something to your liking. Other then that no there's no substitutions for users that don't exist.

What is "IF check"?
And do you mean the following?;

1. I create user ID "0" with the name, "Anonymous"
2. When non-user post the comment on guestbook, module shows;
"Anonymous" wrote new entry...

Thank you!

krileon wrote: Please see tutorials within my signature for further substitution usage information. An example of an IF check is as follows.

[cb:if user_id<="0"]Anonymous[/cb:if]
[cb:if user_id>"0"][username][/cb:if]

Great example!!
Thank you!