There is a known issue in Alert Manager 2010 when creating reminders on Calendar and/or Task Lists. When attempting to set a reminder on this type of list, the user receives the following error:
"Failed to evaluate reminder 'Reminder :: item 1'. ItemId"
There is no known resolution date and no workaround for the issue at this time.
** PLEASE NOTE - Our Known Issues are numbered by the support ticket that led to the creation of the forum post and are not cumulative in regards to total issues for a specific product **