# Blender 2.65 (sub 8)
Traceback (most recent call last):
  File "/home/bill/.config/blender/2.65/scripts/addons/io_qfmap/entity.py", line 96, in poll
    reg.callback_add(draw_callback, (cls, context), 'POST_VIEW')
AttributeError: 'Region' object has no attribute 'callback_add'

location: <unknown location>:-1
  # Error

# backtrace
/home/bill/src/blender/build_linux/bin/blender() [0x8cbe66]
/lib/x86_64-linux-gnu/libc.so.6(+0x324f0) [0x7fa857e6b4f0]
/usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so(+0x21f51b) [0x7fa84bf4a51b]
/usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so(+0x21eb7f) [0x7fa84bf49b7f]
/usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so(+0x21fbab) [0x7fa84bf4abab]
/usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so(+0x3267fb) [0x7fa84c0517fb]
/usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so(+0x31f8c3) [0x7fa84c04a8c3]
/home/bill/src/blender/build_linux/bin/blender() [0xd4783a]
/home/bill/src/blender/build_linux/bin/blender(draw_mesh_textured+0x8df) [0x9abcbf]
/home/bill/src/blender/build_linux/bin/blender() [0x9966f3]
/home/bill/src/blender/build_linux/bin/blender(draw_object+0xe6b) [0x99a5ab]
/home/bill/src/blender/build_linux/bin/blender(view3d_main_area_draw+0x6e4) [0x9708d4]
/home/bill/src/blender/build_linux/bin/blender(ED_region_do_draw+0x2ed) [0xb193cd]
/home/bill/src/blender/build_linux/bin/blender(wm_draw_update+0x5a8) [0x8cfa48]
/home/bill/src/blender/build_linux/bin/blender(WM_main+0x28) [0x8ccc08]
/home/bill/src/blender/build_linux/bin/blender(main+0xb2f) [0x8be7ff]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7fa857e57ead]
/home/bill/src/blender/build_linux/bin/blender() [0x8ca869]