Members access functions but cannot enter subforums

To whom it may concern,
I have been getting numerous reports from forum members saying they can access most of the forum functions, but are unable to go to their respective sub-forums. When they click on the forum they are asked to log in again. When they do, they are told the forum does not exist.

Here is a sample complaint from a member:

"For 2 days now I have not been able to browse the forums. I can get into my messages, profile, memberslist, calendar, and search with no problem. But when I get into usergroups and click on a clan, I get disconnected and when I log back in I get a message that says this usergroup does not exist.
Do you know what would cause this and can you help me?"

The problem seems to be intermittent and has not yet happened to me directly. There don't seem to be any major settings changes. What is going on?

Thank you.

-S

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