Animation failure

[11viclaw]

First time modelling in 3D and made an armature for my model. Skinned it using the automatic option and gave it a simple walking animation. Everything seems fine and then I press play and this happens:
and it just slides off the bottom of the screen. The arms stay weirdly in place though. Anyone have any ideas? I need it for a uni assignment and it's getting rather upsetting.

Thanks =)