FRAPS sometimes not recording audio?

Sometimes FRAPS will record the video but not the audio, which gets very annoying.
Do I have to update or is this a bug with my computer, btw apparently other people have been having the same problem so I don't think its my computer.

This happens because of a plugin, I think. Or perhaps it's the game. Happened in some of my recordings.

Replying to #2

Found out it was outdated.