Have you checked your connections? Also, are you using optical or USB? You might try a different cable.
I don't know for sure that these things will solve your problems. But connections and bad cables are the easiest to troubleshoot first.
Also, do you have another computer you can test your setup on? Perhaps a friends? If you rule out the cables being a problem AND it happens on another computer, you can guess that the problem is the Modi/Magni. If it doesn't happen on your friends computer and you have ruled out cables, then you can know that the problem is something related to your computer.
This is always the first step in troubleshooting--figure out how to rule things out.