How do you go back a version to

I am using Audacity 2.0.5. I have been trying to edit video files. I know that Audacity is an audio DAW, but I recently learned that it was possible to import a file through ffmpeg and seperate the audio from the video. I followed the Audacity instructions about setting up Audacity so that it would do this. Then I found instructions on where to locate the libraries when this was done, but I got an error message.
I am using Ubuntu 14.04. What I discovered is my computer has Is there a way to change it to 53? My goal is to make tutorial videos to help other people, but so far they are either to quiet or have a lot of hum. Thank you all for your help in advance.

That error is not related to FFmpeg.

What has happened is that the recording has stalled as soon as you started recording.
What are you trying to record and what equipment are you using?
Are your speakers really connected via S/PDIF?

The image in the post was not accurate. Sorry about that, wrong file. This is the correct error message.

At this point we need the information requested in the pink box above.
Where did you get Audacity and how did you install it?

FFmpeg is a problem on Ubuntu because it is no longer in their official repository (they have switched from FFmpeg to libav).

The easiest solution is likely to be to use some other program to convert the files. Does Ubuntu have WinFF?