Shader syntax error ? Where did I go wrong?

Hi, I wrote this simple shader for a test

static const char* VShaderText =
    "vs_1_1\n"    "dcl_position v0\n"    "dp4 oPos.x, v0, c0\n"    "dp4 oPos.y, v0, c1\n"    "mov oPos.zw, v0.zw\n"    "dp4 oT0.x, v0, c4\n"    "dp4 oT0.y, v0, c5\n";

and assembled it using D3DXAssembleShader, quite easy eh ? Yet it always fails and give "Syntax error" error message ? I know I've used this shader before and strangely this time it won't work.. Any ideas ?