Shader - Too many TEXCOORD

Hi,
I’m receiving the error “TEXCOORD” has too big of a numeric index (8). I understand what this means - but it shouldn’t be occurring as I’m using very few inputs.

struct Input {
	float2 uv_MainTex;
	float3 worldNormal;
	float3 worldPos;
	INTERNAL_DATA
};

Is all I’m using. I get the feeling INTERNAL_DATA is filling the shader with a lot of unnecessary junk - the only reason for using it is to get WorldNormalVector. What’s very odd is it doesn’t matter if I reduce the number of inputs (I removed uv_BumpTex and this did not help).

Thanks in advance!

Did you read http://forum.unity3d.com/threads/64876-world-normals-and-surface-shaders, which seems to describe exactly your problem and some possible solutions to it?