We're using sbs 2003 with exchange 2003 on it. For some reason when my users attempt to share out an event on the calendar, they get an instant send/receive error: "reported error (0x80070057) : 'Could not complete the operation. One or more parameter values are not valid." When I open up the outgoing mail, instead of the normal exchange name for the recipient such as "David", it says something more like "David <o=businessname;ou=servername;cn=users;cn=david>. To me this looks like active directory but I'm pretty sure we don't have AD loaded as its only small business edition. The only temp fix we've been successful with is to manually remove the recipient information and replace it with the full email address, which in this case would be david@businessname.com. Any ideas what this might be? I've checked msn search for various versions of this error message, but its not very descriptive and seems to happen for a lot of varied reasons...