Texture not rendering on quad across various HW platforms.

I happily render a texture onto a quad on the following HW: ATI FirePro V3750 (FireGL)

However, I want to deploy on a low-cost kiosk PC. It's not rendering the quad, but neither is another box here on my bench that has an...

NVidia GeForce 7050 / NVidia nForce 610i (I just updated the driver too, still no luck).

I load the texture using the code below, and I render it in the Paint() method.

****What am I not understanding about HW/SW interplay relating to using textures? Is there a simple fix I am missing? I'm rendering into a GLControl. Do I need to modify the control, or is there something I can do on the texture load or paint below?

static int LoadTexture(System.Drawing.Bitmap bmap)
{

int id = GL.GenTexture();
GL.BindTexture(TextureTarget.Texture2D, id);

Bitmap bmp = new Bitmap(bmap);
BitmapData bmp_data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, bmp_data.Width, bmp_data.Height, 0,
OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, bmp_data.Scan0);

bmp.UnlockBits(bmp_data);

// We haven't uploaded mipmaps, so disable mipmapping (otherwise the texture will not appear).
// On newer video cards, we can use GL.GenerateMipmaps() or GL.Ext.GenerateMipmaps() to create
// mipmaps automatically. In that case, use TextureMinFilter.LinearMipmapLinear to enable them.
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);

return id;
}

public void Paint()
{
if (!_loaded || (_window == null)) // Play nice
return;

_window.MakeCurrent();

OpenTK.Graphics.GL.Clear(OpenTK.Graphics.ClearBufferMask.ColorBufferBit | OpenTK.Graphics.ClearBufferMask.DepthBufferBit);
GL.Enable(EnableCap.Texture2D);

Matrix4 modelview = Matrix4.LookAt(Vector3.Zero, -Vector3.UnitZ, Vector3.UnitY);

OpenTK.Graphics.GL.MatrixMode(OpenTK.Graphics.MatrixMode.Modelview);
OpenTK.Graphics.GL.LoadMatrix(ref modelview);

GL.Begin(BeginMode.Quads);
GL.Color3(Color.White);

// chart boundary...
GL.TexCoord2(0.0f, 0.0f); OpenTK.Graphics.GL.Vertex3(new Vector3(XMIN, -1.0f, -3f));
GL.TexCoord2(1.0f, 0.0f); OpenTK.Graphics.GL.Vertex3(new Vector3(XMAX, -1.0f, -3f));
GL.TexCoord2(1.0f, 1.0f); OpenTK.Graphics.GL.Vertex3(new Vector3(XMAX, 1f, -3f));
GL.TexCoord2(0.0f, 1.0f); OpenTK.Graphics.GL.Vertex3(new Vector3(XMIN, 1f, -3f));
OpenTK.Graphics.GL.End();

_window.SwapBuffers();

}