BleepingComputer.com: Outlook Calendar Sharing-"Access Denied" error

I am having a problem with sharing Outlook calendars in a NON-Exchange environment. I have a small non-profit office of 7 workstations and 4 of the user's need to share our calendars as well as a "group" calendar. We are running a brand spanking new environment featuring Windows 7 professional 64-bit, Office Professional 2007 (i.e. Outlook 2007) and using both IE8 and Firefox browsers. I have tried adapting all previous fixes that I could find for Vista/Outlook 2007 (regarding cookies and also running in protected mode when using IE6/7 [Firefox does not appear to have a similar feature]). I sequence thru the request for logon to my Live account, receive a message: "Access to resource denied. If you have signed into and saved your Windows Live ID with a web site, sign out of that Web site, then try this operation again.". We get the same error message when trying to subscribe to each other's calendars. Makes me wish we could afford an exchange server! Arrghhh!

I am having the same problem, but I am using XP machines. I am also using IE8 and Firefox browsers and Office 2007. I have tried all of the suggestions that I can find and none have showed any promise.