We have a network of 24 users and all use MS Office 2010 Pro in an MS SBS 2003 environment running Exchange.
One user is reporting that when he sends or receives a scheduled Task to/from someone that his Outlook won't accept it. The specific error in Outlook is "The task cannot be sent. It may be an attachment of another message."
As a work-around the user has been flagging task assignment emails for follow-up with special reminders.