Trouble creating environment map

[user_deleted]

I'm trying to render two spheres with a shader I got from "Essential Renderman Fast" by Ian Stephenson.  Unfortunately, I keep getting errors:

chriss@mazindol:...testing/in/chris_renderman/essential_renderman/chap24>render test_spheres.rib
P01001 {ERROR}   Unregistered request: "fov" (at line 8 in test_spheres.rib)
P79014 {ERROR}   RIB syntax error (at line 8 in test_spheres.rib, last token 'fov').
T02001 {ERROR}   Can't open texture "envmap.jpg" [ Object: Shader: reflective]

The error seems to originate from rib at the MakeCubeFaceEnvironment command.  Here is the text of my rib file:

Display "test_spheres.tiff" "file" "rgb"
Format 640 480 1
Projection "perspective" "fov" [100]

LightSource "ambientlight" 1 "intensity" [0.2]
LightSource "spotlight" 2 "from" [-1 1 0] "to" [0 0 3] "intensity" [3]

MakeCubeFaceEnvironment "posx.jpg" "negx.jpg" "ceiling.jpg" "floor.jpg" "posz.jpg"
"negz.jpg" "envmap.jpg" fov "gaussian" 2 2

WorldBegin
Translate 0 0 2

Surface "reflective"

#Left Sphere
TransformBegin
Translate -1 0 0
Rotate 90 1 0 0
Sphere 1 -1 1 360
TransformEnd

#Right Sphere
TransformBegin
Translate 1 0 0
Sphere 1 -1 1 360
TransformEnd

WorldEnd
I noticed that no environment map is being generated.  Does anyone know what I am doing wrong?  I'm rendering with Pixar Renderman.  Thanks.

[user_deleted]

Here is the code for the shader:

surface reflective
(
float Ka = 1;
float Kd = 0.5;
float Ks = 0.4;
float Kr = 0.3;
float roughness = 0.1;
color specularcolor = 1;
)
{
/*Initialisation*/
normal Nf = faceforward (normalize(N),I);
vector V = -normalize(I);
color Ct;
vector Rcurrent = reflect(I,Nf);
vector Rworld = vtransform("world",Rcurrent);
color Cr = color environment("envmap.jpg",Rworld);

/*Texturing*/
Ct = Cs;

/*Shading*/
Oi = Os;
Ci = Oi * ( Ct * (Ka * ambient() + Kd * diffuse(Nf)) +
specularcolor * Ks * specular(Nf,V,roughness) + Kr * Cr);
}