Blender crash with armatures, does this happens to me only?

[Devas73]

Hello,
I'm trying to study character animation, and doing this good tutorial from Malefico: http://argoslabs.com/~malefico/tutor/walking.html I downloaded the blend file that comes with it:
http://argoslabs.com/~malefico/tutor/ga ... lk_nla.zip
When I select with right mouse button a bone from the armature in pose mode blender crashes.
It happens with 2.23 and 2.27 on win2000.
With other IK constraints configurations blender doesn't crash.
Does anybody had such problems?