you should be able to change your avatar. i see that you don't have one now whereas before you did so i'm guessing that you were in the right place and everything. smulkin may need to look into it for you if you can't figure it out. i'm not sure why it wouldn't be working for you.
I checked settings - there should be nothing keeping you from selecting a different avatar. If it persists just shoot me a PM an I'll dig further - admittedly i am sans coffee at this point in the morning.
Go to User CP, then click edit avatar (you probably know that already) at the bottom of the list showing the avatars we supply, there is a place to upload your own. Hope this helps.
*Jeanne*
"To acquire knowledge, one must study; but to acquire wisdom, one must observe"
Not on my screen there isn't. I thought I was just crazy and was overlooking it, but after 10 minutes of searching my screen, I have come to the definitive conclusion that its just not there lol.