No error is showed - not in the browser - and not in php-log.
When I include event_calendar and do a dev/build?flush=all i get
[10-Mar-2010 10:03:26] PHP Fatal error: Class 'UpgradeSiteTreePermissionSchemaTask' not found in /opt/silverstripe-2.3.6-1/sapphire/core/model/SiteTree.php on line 968
in php-log. But dev/build is producing the expected browser output and the site and cms is running.
But when i navigate to a page in the CMS by clicking it, the turning animation stays forever and the tinymce editor does not open the page for editing.
When i remove event_calendar and do a dev/build?flush=all everything is working fine again without event_calendar.