If FXC is throwing an exception during compilation rather than giving you a compilation error it's probably not anything you've done wrong.
If you're using the DirectX SDK make sure you're using the most recent version (June 2010). If you're using the Windows Kit 8.0 SDK then you may have found a compiler bug. What version of the SDK / fxc are you using?
Can you post a shader that actually compiles (one with the missing VertexShaderOutput struct and without ...'s in place of actual code)? I've filled in the missing code and have no problem compiling it using fxc from Windows Kit 8.0.
EDIT:
Nope, I hadn't spotted you'd commented out the code that made it not compile.
Sure enough, it doesn't compile, but that's because it's not valid code (as reported by the compile errors). You're using the POSITION semantic as an input to your pixel shader, which is not valid. If you want to use the outputted position from a vertex shader as input to a pixel shader, copy it into a second attribute and use that instead. If I substitute the following code into your shader it then compiles:
struct VertexShaderOutput
{
float4 ClipPosition : POSITION; // Renamed this to ClipPosition.
float4 Position : TEXCOORD0; // This is valid to use as an input to the pixel shader.
float3 Normal : NORMAL;
float3 ExactPos : TEXCOORD1;
};
struct PSOutput
{
float4 col : COLOR0;
float dept : DEPTH;
};
VertexShaderOutput VSFunction(VertexShaderInput input)
{
VertexShaderOutput output;
float4 worldPosition = mul(input.Position, World);
float4 viewPosition = mul(worldPosition, View);
output.ClipPosition = mul(viewPosition, Projection);
output.Position = output.ClipPosition; // Copy output position to our other attribute.
output.Normal = mul(input.Normal, World);
output.ExactPos = input.Position;
return output;
}