One thing at a time.

Okay, the texture's loaded.

First: move the D3DXCreateTextureFromFile call and the SamplerState calls to init3d(), following the CreateDevice call, either before or after init_graphics(). Make sure you delete the call from the render_frame function. You only want to create the texture once, and the sampler state only needs to be set once.

Then, I noticed you have to fix the vertex buffer in init_graphics()

memcpy(pVoid, VB, sizeof(CUSTOMVERTEX));

You're copying from VB, not the v[] array, and you only copy 1 vertex, not the entire array.

Change to:

memcpy(pVoid, v, 6*sizeof(CUSTOMVERTEX));

See if that helps.

EDIT: If you still have problems, it would probably be a good idea to repost your code after you've made the changes.