pnmimage crashes if x/y coodinate outside image

[Hypnos]

crashes on: panda3d 1.6.1 on jaunty:

example code:
from pandac.PandaModules import *
i = PNMImage(256,256)
for x in xrange(1024):
  for y in xrange(1024):
    i.setXel(x,y,1)

can eighter segfault or "*** glibc detected *** python: malloc(): memory corruption: 0x0956cd70 ***", depending which values are written, in which order.

for some values it crashes for others it doesnt. it's really not predictable.