File Not Currently Supported

I am really inept when it comes to anything beyond basic knowledge of computers and such, so I need some step by step trouble shooting instructions on how to get certain files that I have on my computer to play on my TV. I can get most videos and music I have downloaded to play on my TV fine, but just recently I have been getting a "File Not Currently Supported" error, specifically I was trying to play a .mkv video and it gives me that error. I can play other video formats like mp4, avi, m4v without an issue. Is there something that I need to do to get these files to play? I have read other posts and they talk about transcoding, and static IP and I have NO idea what they mean by that stuff and I would really appreciate any help! Thanks!!

[xXsamXx1991]

The first you should do is to follow these steps and post the result here.
viewtopic.php?f=5&t=19

Also the name of your device is helpful and the profile that you use in Serviio for this device.
Further you can take a look at this.
http://wiki.serviio.org/doku.php?id=header_com