glCopyTexImage2D error - GL_INVALID_ENUM

OpenGL Development
#1

I have a problem with glCopyTexImage2D - look at this util method which is cutting previously rendered scene to the texture:

    public static Texture cutRenderToTexture(GL g, int width, int height) { 
        IntBuffer buff = Buffers.newDirectIntBuffer(1); 
        g.glGenTextures(1, buff); 
        int tex = buff.get(); 
        g.glBindTexture(GL.GL_TEXTURE_2D, tex); 
        checkGLError(g); 
        g.glCopyTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA, 0, 0, width, height, 0); 
        checkGLError(g); 
        g.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT); 
        return TextureIO.newTexture(tex, GL.GL_TEXTURE_2D, width, height, width, height, false); 
    }

checkGLError is a simple method which is checking all possible OpenGL errors - in this example I am calling it twice to show that problem can be related only to glCopyTexImage2D call. I am getting GL_INVALID_ENUM error, but target is valid, GL_TEXTURE_2D enabled and OpenGL docs ( https://www.opengl.org/sdk/docs/man4/xhtml/glCopyTexImage2D.xml ) do not specify if this error can happen in any other case.

Any ideas what is wrong?