Comment 21 for bug 1244619

Experiencing same issue here. Running Lightning 2.6 (09/19/2013 last update) isn't displaying any calendars at all. Running TBird 24.0.1 on Linux. This is the error in the console when I try to view a calendar:

Timestamp: 10/14/2013 09:22:51 AM
Error: TypeError: Components.classes[cid] is undefined
Source File: resource://calendar/modules/calUtils.jsm -> file:///home/XXXXXXX/.thunderbird/XXXXXXX.XXXXXX/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calUtils.js
Line: 22

Timestamp: 10/14/2013 09:23:18 AM
Error: [Exception... "'[JavaScript Error: "Components.classes[cid] is undefined" {file: "resource://calendar/modules/calUtils.jsm -> file:///home/XXXXXXX/.thunderbird/XXXXXXX.XXXXXX/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calUtils.js" line: 22}]' when calling method: [calICompositeObserver::onCalendarAdded]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: resource://calendar/modules/calUtils.jsm -> file:///home/XXXXXXX/.thunderbird/XXXXXXX.XXXXXX/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calUtils.js :: notifyFunc :: line 1265" data: yes]
STACK: undefined
Source File: resource://calendar/modules/calUtils.jsm -> file:///home/XXXXXXX/.thunderbird/XXXXXXX.XXXXXX/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calUtils.js
Line: 1267

Updating to 24.0.0 from link above resolves problem.