Don you wrote me about this a week ago or so, and I responded, but never heard back from you. Can you tell us an example of a particular group you belong to that you have this issue with? At least then I can check that you already belong to the group, and start from there in helping you.
Also, as I asked you prior: when you have this issue of not being able to access a group you are a member of... are you sure you are LOGGED IN on the site when you try to access the group? I ask this because any person who is online looking at fotmd.com would be able to see the site and many of the site pages... but they would not be able to see the content of groups unless they were logged into the site. If you see your NAME in the top right hand link bar, then you are logged IN. You should check that because what you describe sounds like that may be what's going on. To see the contents of any Group you are a member of, you need to be LOGGED IN to the site.
Those irritated by grain of sand best avoid beach.
-Strumelia proverb c.1990