VP problem on FX5200

[Coluna]

Hi;
The VP to my terrain renderer works in my geforce2mx(and in 4mx too), but not in my FX5200...the terrain is rendered in black(if i disable blend)...here is the code

!!ARBvp1.0
OPTION ARB_position_invariant;
#61 - cam pos
#62 - .y - scale of tex0 .w - fog
#63 - .y - scale of tex1

PARAM camera = program.local[61];
PARAM fator0 = program.local[62];
PARAM fator1 = program.local[63];
PARAM half = {0.5 , 0.5 , 0.5 , 1.0 };
PARAM one = {1.0 , 1.0 , 1.0 , 1.0 };
PARAM zero = {0.0 , 0.0 , 0.0 , 0.0 };

ATTRIB vpos = vertex.position;

OUTPUT oColor = result.color;
OUTPUT oTex0 = result.texcoord[0];
OUTPUT oTex1 = result.texcoord[1];

TEMP dist, inverso;

MAD oTex0.xy, vpos.xzyw, fator0.y, half;
MUL oTex1.xy, vpos.xzyw, fator1.y;
#i use the squared dist from vert to camera to calculate an alpha value
SUB dist, vpos, camera;
DP3 dist.w, dist, dist;

MUL inverso.w, dist.w, fator1.w;
MUL inverso.w,inverso.w,inverso.w;

MIN inverso.w, one.w, inverso.w;
MOV oColor , one;
MOV oColor.w, inverso.w;
END

First i draw the z pass, then enable blend and draw the terrain using this VP...please help me