I'm assuming that you're getting this error when
making an album, not when uploading the finished album to the server.
One quick thing to try:
- Launch jAlbum.
- Now choose Tools > Open Directories > Config directory. This will open a File Explorer or Finder window.
- Shut down jAlbum.
- In File Explorer or Finder, open the bin directory.
- Delete ffmpeg.exe.
- Launch jAlbum again - this will force jAlbum to fetch a new copy of the ffmpeg executable.
Now try to make the album again.