atlas fails at 50596px but succeeds at 36400

gistfile1.txt

[INFO              ] Logger: Record log in /home/clyde/.kivy/logs/kivy_13-12-30_14.txt
[INFO   ] Kivy v1.8.0-dev
[INFO              ] Atlas: create an 50596x50596 rgba image
[WARNING           ] stderr: Traceback (most recent call last):
[WARNING           ] stderr:   File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
[WARNING           ] stderr:     "__main__", fname, loader, pkg_name)
[WARNING           ] stderr:   File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
[WARNING           ] stderr:     exec code in run_globals
[WARNING           ] stderr:   File "/usr/lib/python2.7/dist-packages/kivy/atlas.py", line 388, in <module>
[WARNING           ] stderr:     ret = Atlas.create(outname, filenames, size, use_path=use_path)
[WARNING           ] stderr:   File "/usr/lib/python2.7/dist-packages/kivy/atlas.py", line 320, in create
[WARNING           ] stderr:     out.paste(fb[0], (fb[2], fb[3]))
[WARNING           ] stderr:   File "/usr/local/lib/python2.7/dist-packages/PIL/Image.py", line 1095, in paste
[WARNING           ] stderr:     self.load()
[WARNING           ] stderr:   File "/usr/local/lib/python2.7/dist-packages/PIL/Image.py", line 608, in load
[WARNING           ] stderr:     if self.im and self.palette and self.palette.dirty:
[WARNING           ] stderr: SystemError: error return without exception set