I get the following error on the error console when I accept a meeting invitation:
Error: Assert failed: error on iTIP processing
2: [file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calItipUtils.jsm:583] ItipOpListener_onOperationComplete
3: [null:0] null
4: [file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calUtils.jsm -> file:///homes/sbansal/.thunderbird<email address hidden>/js/calExchange.js:389] anonymous
5: [file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calUtils.jsm -> file:///homes/sbansal/.thunderbird<email address hidden>/js/calExchange.js:356] anonymous
6: [file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calUtils.jsm -> file:///homes/sbansal/.thunderbird<email address hidden>/js/calExchange.js:327] anonymous
7: [file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calUtils.jsm -> file:///homes/sbansal/.thunderbird<email address hidden>/js/calExchange.js:406] anonymous
Source File: file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/modules/calUtils.jsm -> file:///homes/sbansal/.thunderbird/s5x1fjzl.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calUtils.js
Line: 975
I get the same error too.