Exception in rendering!

Message: Cannot call method 'get' of undefined

TypeError: Cannot call method 'get' of undefined
    at <eval>:92369:30
    at <eval>:17138:46
    at List.__iterate (<eval>:16328:13)
    at IndexedIterable.mappedSequence.__iterateUncached (<eval>:17137:23)
    at seqIterate (<eval>:14726:16)
    at IndexedIterable.IndexedSeq.__iterate (<eval>:14442:14)
    at IndexedIterable.mixin.toArray (<eval>:18380:23)
    at new List (<eval>:16187:62)
    at reify (<eval>:17692:37)
    at List.mixin.map (<eval>:18523:14)
    at Topic.render (<eval>:92366:43)
    at ra (<eval>:45829:322)