layout qualifier with ivec4

[James A.]

I am having a little trouble with my shader:

This doesn't work, I get a linker error

#version 420 core
layout(location = 0)    in vec4 inVertex;
layout(location = 1)    in vec4 inColour;
layout(location = 2)    in vec3 inNormal;
layout(location = 3)    in vec4 inJointWeight;
layout(location = 4)    in ivec4 inJointIdx;
//...rest of the shader omitted, but i don't even use inJointIdx

these two both work:
changing the ivec4 to a vec4:

#version 420 core
//..same at above...
layout(location = 4)    in vec4 inJointIdx;

and removing the layout qualifier but keep it an ivec4:

#version 420 core
//..same at above...
in ivec4 inJointIdx;

Any ideas what the cause could be? I am using Windows 7, GTX 460 with 306.23 drivers.

Thanks for any help

[James A.]

some extra information:
using : in ivec4 inJointIdx;
if I use inJointIdx for something trivial in the shader, and query it's location it gives me "4", but still won't let me manually set it using location to 4

[Alfonse Reinheart]

I get a linker error

What linker error?