When you convert your files and meet such an error message, please contact us with version no. of your program and we will check whether you are using the latest version. At the same time, you need confirm whether your source file can be played successfully on your computer. If it can, please refer to the following information. And please change another format as the output format for a try again. If another format also does not work, you could send us your source file to have a test on our side.