Chances are the DVD uses Dolby Digital/AC3 for the audio. So, you'd need to make sure that the Dolby Digital Stereo decoder is activated in the software in order for the import to work properly. If you still seem to have problems getting on with this or getting the Dolby decoder activated, you might want to contact Magix sales/support: http://support.magix.net
Actually, if you bring in Dolby Digital material and the lack of the Dolby decoder is really the problem here, the activation dialog should come up automatically. If that doesn't seem to work for you or the problem seems to be somewhere else, you might want to follow my previous suggestion and contact Magix directly. I hope you can get it sorted out.