Upgrading Drupal

In my site's forum I can view the posts that administrators or logged in users have posted. But I can't view those that guests and logged out users have posted. What is the problem? It says 3 new messages, but when I click it it doesn't show anything...
When I was logged out and posted new forum topic, after clicking 'Save' it said 'Page not foun'. Any suggestions?

Hi,
I need a module that can display my site's forum discussions. For example, when any user sends their questions or writes a topic I want them to be displayed in my forum. I already created forum, but need a module to display that. Any suggestions?

In the process of upgrading d5 to d6 I noticed the top row of tabs on a user's profile doesn't wrap anymore as it did in d5. Instead, it goes right off the right side of the page also causing a lot of background color to show. This is in the Garland theme. Here's a screenshot. Anyone know (exactly) how to fix this? Thanks.

Please give instructions how do I find myself to "sites/all", where I should create a new directory for the update files? How do I create a new directory there? Thanks in advance for your quick response.

Hi,

first of all, I have not used Drupal before I got chosen for updating some website that uses Drupal 4.7.4 since 2006 and has not been maintained since.

I did the upgrading in a sandbox from an empty 4.7.4. to 5.22 to 6.17 just to get a feeling for it. That works just fine.

In the process of upgrading to 6.17 something went wrong and now I am missing a large number of menu items in the admin menu, links like Modules, Menus, Themes, Triggers and Views are missing from the Menu. I tried the direct links and they don't work either. The site is currently in Maintenance mode. Any idea what might have been damaged?