Getting message "no playable file"

Greetings, I am a newbie to Serviio. I have a Sony Media Player SMP-N100 that I'm working with. I have a program called Vuze where you can download movies, music etc. It has a way where I can take downloaded movies and have them transcoded for the media player. I can see Serviio through the media player and I also see folders like movies, downloads, etc. But when I open those folders a message comes back saying "no playable files". I can also see Vuze and its folders but when I try to access those folders the same message pops up. What can I do to make it right?

[NX3]

What format are the the files?
Have you got transcoding enabled?

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I have the same problem. It seems to display it for just about everything except really small sized photo files (less than 1 mb). Any ideas?