What is the device (connectiong the VCR to the computer) you are recording from?

It appears that whatever that device is may not be connected correctly or the drivers supporting that device need updated or... possibly the audio driver for that device is not selected by the Magix software.

When you record in the Magix software, it opens a recording setup, in there it should have a field for the audio that you select the correct source.

I hope that helps...