This bit fo shader code crashes an ATI X1550. It seems to be the texture lookup affecting the texcoords of subsequent lookups. The shader doesn't fail to compile, it just crashes when it is drawn. The ATI 3870 doesn't have this problem. I think the newer cards use a different driver or something.
 Code:
	vec2 wobble = ( texture2D(texture5,vec2(texcoord.x/32.0 + AppTime / 50000.0,texcoord.y/32.0)).xy-0.5 ) * 0.1;
	
	float waterheight;
	vec3 normal;
	vec4 bumpcolor;

	bumpcolor  = texture2D(texture1,vec2(texcoord.y/wavesize,		texcoord.x/wavesize + AppTime / 50000.0));
	bumpcolor += texture2D(texture1,vec2(texcoord.y/wavesize+0.5,		texcoord.x/wavesize - AppTime / 50000.0));
	bumpcolor += texture2D(texture1,vec2(texcoord.y/wavesize/4.0,		texcoord.x/wavesize/4.0 + AppTime / 50000.0 / 2.0 ));
	bumpcolor += texture2D(texture1,vec2(texcoord.y/wavesize/4.0+0.5,	texcoord.x/wavesize/4.0 - AppTime / 50000.0 / 2.0 ));