This post was in response to a now banned user who was posting questions copied from other users
Assuming these are VoIP calls like Skype then you won't easily be able to correct the volume imbalance and also both parties to the call will be mixed together instead of in separate channels.
Use a recording application meant for recording VoIP calls. If it's Skype try Pamela http://www.pamela.biz/ or MP3 Skype Recorder: http://voipcallrecording.com/.
Note that the current Audacity version is 2.1.2 which you can obtain from our site http://www.audacityteam.org/download/.