- NOTE *** This issue applies only to Calendar 2.0 for Drupal 5. The rewritten Calendar 2.0 for Drupal 6 module (6x-2.0-rc1) does not currently include any support for iCal feeds and hence can NOT be used to display CiviEvent events.
Ical in drupal is not compatible with new Calendar release 2.0 which is currently in development. Ical does not parse properly and generates a warning: Invalid argument supplied for foreach() in /public_html/drupal/sites/all/modules/calendar/calendar_ical.module on line 107.
The calendar works fine with ICS files from 2 other sources. THIS IS REPEATABLE in the CIVICRM 2.0 demo sandbox. It seems to be a parsing error related to the way that civi builds the ICS.
See calendar 5.x-2.dev (http://drupal.org/node/92594/release) NOTE this relies on the new Date module in dev also.
They have completely re-written the Ical parser. It works fine with Google and 2 other Ical services but does not work with Civi 1.9. I thought it could be a permission issue with event registration rights, but I can read the civi Ical directly from the web address (I couldn't verify the ACL on the sandbox 2.0 because I don't have permission.) so I have ruled that out.
I already noted the issue in the module Issue (but I doubt they can test with civi.) This is not a timezone issue, however it was because of the timezone issue that I tried this module. Apparently the 2.dev version will fix the timezone issue.
Copy from Forum Thread (http://forum.civicrm.org/index.php/topic,2368.0.html)