Final Cut Pro X output to compressor

When exporting my 21 minute video, it only gets to 11 minutes and then stops. I get no error messages or any sign that anything is wrong. My first time I ran it through, it worked fine. It only seems to give me a problem when I'm outputting to DVD files (mpeg2 with separate audio file). I did change out one segment of audio. Any help would be appreciated. Thank you!