Probably on one of the slides you did mistakeas this is not related with theme at all. This usually happen when something has been broken in one of the slides so you need to check all your slides and remove all mistakes/errors.
Manually of course. If you built those slides, you should know where the problem can be. But if you have no idea, then you can use for example Firefox in html mode (CTRL+U) and you can check where the red colored code is what means errors. This is the only way to check where the mistakes probably are. Problems like this one can`t be solved with with magic plugin or tool This is manual work which sometimes is hard when you look for the mistakes and errors,
Comments
Probably on one of the slides you did mistakeas this is not related with theme at all. This usually happen when something has been broken in one of the slides so you need to check all your slides and remove all mistakes/errors.