Maybe it's just me, but in general I think that people making screen casts or other sound based productions often forget that others may not be familiar with a local broad accent. This goes for the CC staff too when they are making their help videos.
I listened to the screen cast, and I had to play it twice before I understood what you were saying. You are not speaking too fast, but I have problems with your accent.
Well, I don't know what another American, from a different part of the States would say, but I'm not an American, nor am I a native speaker of English, so to please me you would have to, well, speak standard British English, I guess
Your explanations, after having listened to them twice, I'd say are very good. Yes, you do get your message across.