I can't seem to upload a battle sprite I slapped together for the Heaven Knight class. I've checked, and it meets the dimension and file type requirements. I'm supplying a direct link, too. I've tried with other sprites, and they have all resulted in the same message: "Staff sprite could not be loaded!"

I've tried this several times over the course of about three days, and the result never changes. Am I doing something wrong? Is sprite uploading bugged right now? Am I just experiencing an error that nobody else is?