Here's a checklist:
Is it the correct file you uploaded?
Is it in 128x128?
Does it contain any colored pixel (Not white and black)?
Is it un-compressed? (Uncheck the box that says RLE compression)
If you can answer yes to the following, wait till tomorrow, and if it doesn't work, save it as a .png and upload that instead.
I also noticed that I can't upload my new textures. So, I think it's something else than what you guys said.