Please make sure you are uploading a supported file type." In this case, I suggest you to convert your video file to another format like:
You can use free programs like Windows Live Movie Maker to add an image to an audio track so you can convert it into a .WMV video file. After you’ve converted the file, you can then upload it to YouTube.
Here’s how you convert audio tracks into .WMV video files on Windows Live Movie Maker:
Part 1: Select your audio and image files
Select Add videos and Photos from the bar at the top, then choose an image from your computer. This image will be displayed in your slideshow.
Click Add music and select your audio track.
Part 2: Adjust the image to fit the audio track
To make sure the file is properly uploaded on YouTube, you’ll need to adjust the duration of the image to match the duration of the audio track on your timeline. Double click the green audio bar in the timeline, which will display “End point”. Copy the End point number (e.g. 261.49). Double click the image thumbnail in the timeline, and enter a duration equal to the length of the audio track. For example, if the audio track has a length of 261.49 the image duration should be adjusted to 261.49 as well.
Part 3: Save your file
Choose Recommended for this project.
After naming your movie, click Save.
Once .WMV video file is done, you can go back to YouTube and the video will be uploaded.