Ok, this may sound obvious - but I just ran into this and I was truly surprised. I'm doing some work for a client who uses CrystalTech. They have a pretty nice web based administrator. But get this - if your session times out and you try to load a page, you get this error:
You are either attempting to access a page that does not exist or your session has expired. See your host's website for the correct URL or to preview the features of Webcontrolcenter.com
So I see this and I say, ok, let me just login again. I reload - and I get the same message. I leave the URL I'm on and just go to the home page, www.webcontrolcenter.com and I get the same thing. I look - and for the life of me - can't see anyway to log back in. I have to go back to CrystalTech to find out that the URL to login is www.webcontrolcenter.com/customer.aspx. Couldn't they have added a link to that?