Oracle Management server jobs fail

I set up an OMS to perform nightly backups, exports, and analyzes. I scheduled a job to analyze a schema and another job to export a schema. Both jobs scheduled at different times failed. I look at the history of the job and all it says is failed. No explaination. I tried searching for files created or modified at the time the job was scheduled to run but can't find any file that relates to the jobs. It is difficult to fix a problem when you don't know what the problem is. Is there any file that tracks these jobs? I looked at the alert log of the DB I was trying to export and no notice of any errors.