Yes, I've had problems with camtasia too - I'll give you some other recording software, which I've used in the past and had a great experience for me. However, I'm sure that some others in this community may have better option(s).
1). Bandicam - Does quality recording, just like Fraps and its pretty good. If you don't like the FPS showing on the top I think you can disable it but I'm not sure. I know for certainty it does record audio and I've had good experience with this. However you can record a maximum of 10 minutes per file when you are not registered. You can become registered by other ways, such as pay.. and other things that probably shouldn't be said.
http://www.bandicam.com/downloads/
2). Dxtory - Quality recording and decent audio. It's one of the best free recording software around I think, I've actually never had a problem with this and others will probably agree. This would be my personal recommendation but you'll have to get used to it!
http://download.cnet.com/Dxtory/3000-13 ... 05596.html
3). Audacity - Urgh.. not to sure about this, takes some effort to get used to and I personally don't like the interface but you may like it. I don't have much experience but if you do tend to use this the audio would be great - that's one of the good things about it!
http://audacity.sourceforge.net/download/
I personally wish you the best with whatever you decide to use. Listen to others first though, incase you want to hear more about other programs!