The lines that error are both:
diffuseColor = DiffuseAndSpecularFromMetallic( diffuseColor, _Specular, specularColor, specularMonochrome );

And the error is Shader error in 'Custom/PlatformBaseS': Program 'vert', parameter of type 'half3' is a function output and does not permit argument of mismatching type 'float3' at line 267 (on psp2)

It appears that the metallic shaders aren't supported on the PSVita? is this a known issue?