The project pages are not exposed anywhere on the site to the public just yet.  I believe this will happen within the next week or so but don't hold me to that.

You can also view my Forum blog, from this page, to keep updated on the status and going ons of the module.

1)  Is there a way for all users to have access to the forum's search button?

This is available to all users who can see the module, logged in or not.  The reason you may not be seeing it actually involves the module's container.  This module makes the most of module actions and their security control.  The downside is that it does require a container to show those actions.  We found this out after we already took this route, we didn't change it though because we are think the core should change and not the module.  This is still being discussed though at this time.

2)  When I search using the portal's search box (not the forum's search screen), it returns a list of posts that match.  When I click on a post it gives me this error:

If you can, please check the error logs and post back here.  My first suggestion, to test, is to disable the navigation from the forum's configuration settings.  (The solpart menu)  My guess is that this is causing the problems.  Disable it, then repeat the steps to see if it caused an error.  Please post the results back.