顶点着色器无法编译。找不到错误

编辑：

似乎错误是，不允许我在单独的线程中编译着色器？由于我刚才一直在将对象加载推入线程环境中，因此出现了错误消息。只是不认为这可能是它的原因。

我当前的顶点着色器由于某种原因无法编译。我收到的错误消息不存在，并且找不到错误。

uniform mat4 u_MVPMatrix;       
uniform mat4 u_MVMatrix;        
uniform vec3 u_CameraPos;

attribute vec4 a_Position;      
attribute vec4 a_Color;         
attribute vec3 a_Normal;        

varying vec3 v_Position;        
varying vec4 v_Color;           
varying vec3 v_Normal;          
varying vec3 v_CameraPosition;
varying vec4 v_Ambient;         

void main()
{
    v_Position = vec3(u_MVMatrix * a_Position);

    v_Color = a_Color;

    v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0));
    //v_CameraPosition = vec3(u_MVMatrix * vec4(u_CameraPos, 0.0)); // taken out to debug
    v_CameraPosition = u_CameraPos;

    gl_Position = u_MVPMatrix * a_Position;
}

这一个的片段着色器是：

precision mediump float;        

uniform vec3 u_LightPos;        
uniform vec4 u_Light;
uniform vec4 u_Ambient;
uniform vec3 u_LightDirection;
uniform vec3 u_CameraPos;

varying vec4 v_Ambient;        
varying vec3 v_Position;        
varying vec4 v_Color;           
varying vec3 v_Normal;          
varying vec3 v_CameraPosition;

// The entry point for our fragment shader.
void main()
{
    float distance = length(u_LightPos - v_Position);
    vec3 lightVector = normalize(u_LightPos - v_Position);

    float diffuse = max(dot(v_Normal, lightVector), 0.1);

    diffuse = diffuse * (1.0 / (1.0 + (0.25 * distance * distance)));

    // specular lighting removed due to debugging

    gl_FragColor = v_Color * (u_Ambient + (diffuse * u_Light));
}

“正在尝试”以获取错误消息：

Log.d(TAG, "Compilation -> " + GLES20.glGetShaderInfoLog(iShader));

从方法返回空字符串，以及

Log.e(TAG, "Vertex Shader Failed -> " + GLES20.glGetError());

仅返回0。

我正在为Android的OpenGL ES 2.0开发，如果我没有意识到对Android的任何限制？

感谢您的任何帮助！