Sometimes Garageband just stops recording for seemingly no reason?

It comes up with a message saying that “part of the project couldn’t be played” and that I should look into “optimizing performance”. It’s recording on a MacBook Pro with 4GB of RAM, with only Garageband and Safari open.

What’s the problem? I’ve even changed the audio driver to “maximum number of simultaneous tracks”, and followed everything on the optimizing performance guide on the Apple help site.

Any suggestions? Our podcast is taking ridiculously long to record this week because it keeps cutting out.

Thanks guys!