"Invalid vertexgroup" error when exporting walking character

I found this great character in a tutorial and when I try to export it to sio2 the exporter says:
"ERROR: invalid vertexgroup: plane:hip.r."
http://wiki.blender.org/uploads/9/96/BSoD-ItCA-final.blend

Any idea what this can be and/or where I can read about valid "vertexgroups" the exporter accepts?
Most importantly, how can this be fixed so that the export succeeds?

Thanks

michael

ps: Here is the source tutorial:
http://wiki.blender.org/index.php/Doc:Tutorials/Animation/BSoD/Character_Animation#Finished_product

The vertexgroup contain no vertices...

Thanks for the reply. Does that mean the tutorial has an incompatible way of using armatures? Is there an easy way to fix this?

Not really... just make sure that all vertexgroup that you have contain some vertices attached... that's all

Hi,

I'm also getting this problem after rigging and posing one of my first models... so the model exported fine until I added the rigging, now that I have added the rigging it won't export saying invalid vertex group messages for the bone objects.

I didnt quite understand when you said "just make sure that all vertexgroup that you have contain some vertices attached" - how does this relate to the bones or rigging?

Any info here would be useful.

Many thanks...

further to this, I can see that it looks like for every bone I've added its created a vertex group. Based on the above, I'm assuming some of them have no vertices included..... is there any way to check this? When I select the vertex group I'm finding it hard to see any way to do this....

Is there a better approach to rigging a model that will preven this from happening?

Hi, you might want to try use automatic skinning instead of the manual process... look here for the "Create from Bone Heat" option:
http://wiki.blender.org/index.php/Doc:Manual/Animation/Armatures/Mesh_Skin_Weighting

There's an excellent tutorial in Issue 118 of 3D World, look for the "Art of Rigging in Blender with Christopher Plush" from the Yo Frankie team:
http://www.3dworldmag.com/page/3dworld/20090526

And, you might want to try a different rig... I like Audine:
http://thelowlander.wordpress.com/download/

--yarri