Displayotron Hat IOerror[Errno 5]

When I run backlight.py (sudo ./backlight.py) I get the following error:
Traceback (most recent call last):
File "./backlight.py", line 9, in
import dothat.backlight as backlight
File "/usr/local/lib/python2.7/dist-packages/dothat/backlight.py", line 1, in
import sn3218, colorsys, math
File "/usr/local/lib/python2.7/dist-packages/sn3218.py", line 112, in
enable_leds(0b111111111111111111)
File "/usr/local/lib/python2.7/dist-packages/sn3218.py", line 60, in enable_leds
[enable_mask & 0x3F, (enable_mask >> 6) & 0x3F, (enable_mask >> 12) & 0X3F])
IOError: [Errno 5] Input/output error

When I hello_world.py (sudo ./hello_world.py) it works OK.

I'm using 3.12.35+ #730 PREEMPT Fri Dec 19 18:31:24 GMT 2014 armv6l GNU/Linux