Yes, agree with Alice. You need more oxidant (strongest one being bleach) and/or enzymes (from mainstream detergent or Bac-out). If you use bleach, add it to your hot/main cycle, the HE washers have a special bleach compartment. It doesn't take much to do the job. Good luck, let us know what you do and how it goes.
I used to be so paranoid about bleach, I hated the smell and thought it was eco unfriendly and dangerous for sensitive skin, but the more I researched it the more that seemed irrational (I mean, I'm not morally opposed to swimming pools which are FULL of the "dangerous" chloramines/bleach byproducts).... then I discovered that the regular unscented kind doesn't even have a smell that bothers me! It's really just about diluting it properly but your washer does that for you. I am a total bleach convert for diapers now.