PIL: Transparent PNGs and im.paste: ValueError: bad transparency mask

[Durand]

Hi!

I'm trying to paste a png with a transparent layer into an image using "image.paste(tesla,(20,10), tesla)" but I'm getting this error:

ValueError: bad transparency mask

I have used im.paste(image,box,image) sucessfully before to paste an image with transparency, however, it doesn't seem to work for this particular image. How would I change the image so that it doesn't give me this error?

The image is http://img293.imageshack.us/img293/1434/teslahv5.png

Thanks in advance!