We were assuming that people generally wouldn't try uploading too often so it wouldn't cause problems, but it seems we need to make a workaround of some sort. We may have to disable uploaded avatars.
What's the error say, exactly?
May have to disable avatar uploads altogether, possibly on the wiki also. Maybe I can try and convince her to let me have access change these things when she's back :-/
In the mean time, please refrain from uploading avatar pics, unless there is little activity. It might not cause an error for you, but it probably will for someone else. Heaven forbid two people uploading at once.