Do you not have to use the L4D2 Authoring tools in the Steam Tools sections? (Don't know, I haven't tried compiling for L4D2)

Thanks Artfunkel good to know!

Excellent, Glad I could help!

kk, You will see in that video where I had the "DOH" moment when I realized I had not set the armature modifier. But, it shows you the errors your getting with the process your currently following and then the final successful export after assigning the modifier.

Also, when you compile your model, "I believe" that if you add the $staticprop command in the qc, studiomdl will delete that bone and replace it with a staticprop bone. At least that what i get from reading info on static props.

Here you go, sorry, no audio, this is just a training aid for you.

https://youtu.be/gfAiIqVQ_ns

Give another couple of minute and I'll link you to a video

Nope, I'm an idiot, I forgot a step in that process.

After assigning the mesh to the bone, Add an Armature modifier and point it at the Armature.

If you didn't do that, yeah, everything is set up, but the model doesn't know what bone to use.

It will throw the same error.

Umm, that's the same error you originally posted.

What is the new error?