Using a Drupal 6 tutorial for Drupal 7 I hate making posts like this because I feel like I am asking people to do all my work for  me! However, in times like this, when I am pressed for time, I have to. So...

I am trying to add an user profile in the topics in the Forum module. I have found a brilliant tutorial, but unfortunately it is for Drupal 6 and some of the functions are not compatible with Drupal 7; I couldn't find the equivalent functions, and I figured some of you may know them.

If you do, I would greatly appreciate it if you could share them with me; even if you don't provide the whole of the functions in tutorial (which would be nice), and just provide me with the Drupal 7 functions to replace the ones in the tutorial; anything would help.

The main functions that do not work are the profile_load_profile($user), and the get_user_####($user) functions.

By the way, I am assuming it is because those functions are depreciated in Drupal 7 when it says "Undefined"! I can't see any other reason for it not to work, and I kind of expected some of the tutorials wouldn't work properly on Drupal 6.
Drupal 7 doesn't include the core profile module since users are entities which you can attach fields to. If you have added additional fields to the user you can get them with just user_load().

FYI: it is not advisable to the $user when calling user_load() since $user is a global variable which can cause problems.

It doesn't look like that tutorial would ever fully work since get_user_comment_count() is never defined and the get_user_rank() parameter call's for a comment count but uses the $user object in the user_forum_load() function.

To get the comment count of a user you could just lookup the number of comments from the comment table for a given user and the tutorial's user_comment_rank() should still work.