Just so I have some context, did this happen immediately after you installed the event calendar module? Do you have any other modules running? Give me as many details as you can, especially what led up to the error. Did creating an event ever work?

This is a terrific module but I think I found a typo.

When creating a calendar page, you are prompted to enter the "Number of events to display on default view. (Enter 0 for all events)." If you enter 0 because you want all the events to list, the RSS feed returns 0 events and the default listing displays 0 events. For example, I entered three events for test purposes and entered 0 for the number of events to display on default view. None of the events that I entered were listed on the default view of {site_name}/calendar/. If I enter the URL {site_name}/calendar/2009 or {site_name}/calendar/200903 all the events listed. The same thing happened on the RSS feed.

I believe the instructions on the calendar page should read as -> Number of events to display on default view instead of -> Number of events to display on default view. (Enter 0 for all events)

sorry but i still have the same error saving content - also when i changed the "number of events to display on default view"

as far as i can see the same as before:

Error: Couldn't run query: insert into `CalendarEvent_versions` SET `Recursion` = 0, `CustomRecursionType` = 0, `MonthlyRecursionType1` = 0, `MonthlyRecursionType2` = 0, `ClassName` = 'CalendarEvent', `Created` = null, `LastEdited` = null, `Start` = null, `End` = null, `Content` = null, `Title` = null, `StartTime` = null, `EndTime` = null, `Location` = null, `EventType` = null, `DailyInterval` = '1', `WeeklyInterval` = '1', `MonthlyInterval` = '1', `MonthlyIndex` = '1', `MonthlyDayOfWeek` = '0', `CalendarID` = '0', `RecordID` = 302, `Version` = 2, `AuthorID` = 3 Unknown column 'ClassName' in 'field list'
At line 394 in /Users/tobiaszeller/Sites/sivis_2_3/sapphire/core/model/MySQLDatabase.php

user_error(Couldn't run query: insert into `CalendarEvent_versions` SET `Recursion` = 0, `CustomRecursionType` = 0, `MonthlyRecursionType1` = 0, `MonthlyRecursionType2` = 0, `ClassName` = 'CalendarEvent', `Created` = null, `LastEdited` = null, `Start` = null, `End` = null, `Content` = null, `Title` = null, `StartTime` = null, `EndTime` = null, `Location` = null, `EventType` = null, `DailyInterval` = '1', `WeeklyInterval` = '1', `MonthlyInterval` = '1', `MonthlyIndex` = '1', `MonthlyDayOfWeek` = '0', `CalendarID` = '0', `RecordID` = 302, `Version` = 2, `AuthorID` = 3 Unknown column 'ClassName' in 'field list',256) line 394 of MySQLDatabase.php MySQLDatabase->databaseError(Couldn't run query: insert into `CalendarEvent_versions` SET `Recursion` = 0, `CustomRecursionType` = 0, `MonthlyRecursionType1` = 0, `MonthlyRecursionType2` = 0, `ClassName` = 'CalendarEvent', `Created` = null, `LastEdited` = null, `Start` = null, `End` = null, `Content` = null, `Title` = null, `StartTime` = null, `EndTime` = null, `Location` = null, `EventType` = null, `DailyInterval` = '1', `WeeklyInterval` = '1', `MonthlyInterval` = '1', `MonthlyIndex` = '1', `MonthlyDayOfWeek` = '0', `CalendarID` = '0', `RecordID` = 302, `Version` = 2, `AuthorID` = 3 | Unknown column 'ClassName' in 'field list',256) line 102 of MySQLDatabase.php MySQLDatabase->query(insert into `CalendarEvent_versions` SET `Recursion` = 0, `CustomRecursionType` = 0, `MonthlyRecursionType1` = 0, `MonthlyRecursionType2` = 0, `ClassName` = 'CalendarEvent', `Created` = null, `LastEdited` = null, `Start` = null, `End` = null, `Content` = null, `Title` = null, `StartTime` = null, `EndTime` = null, `Location` = null, `EventType` = null, `DailyInterval` = '1', `WeeklyInterval` = '1', `MonthlyInterval` = '1', `MonthlyIndex` = '1', `MonthlyDayOfWeek` = '0', `CalendarID` = '0', `RecordID` = 302, `Version` = 2, `AuthorID` = 3) line 418 of Database.php Database->manipulate(Array) line 117 of DB.php DB::manipulate(Array) line 830 of DataObject.php DataObject->write() line 641 of LeftAndMain.php LeftAndMain->save(Array,Form,HTTPRequest) line 228 of Form.php Form->httpSubmission(HTTPRequest) line 107 of RequestHandler.php RequestHandler->handleRequest(HTTPRequest) line 121 of RequestHandler.php RequestHandler->handleRequest(HTTPRequest) line 122 of Controller.php Controller->handleRequest(HTTPRequest) line 262 of Director.php Director::handleRequest(HTTPRequest,Session) line 106 of Director.php Director::direct(admin/EditForm) line 115 of main.php