vertexbuffer error?

hey.. ive tried to include the Odyssey UI (http://www.codeproject.com/cs/media/OdysseyUI.asp)into my 3d game but apparentlny the way the menu parts get drawn upon the screen is not really friendly with my sister's pc (which has more-or-less no problems with the 3d part of the whole game). the problem is that the only thing that gets drawn are the texts. in other words, anything made of the vertices is not drawn. i was tracing down the commands chain and came to a point where the HUD builds the vertex/index buffers. this is the code:

		public void BuildVertexBuffer()
		{
            vIndex = numPrimitives = 0;
            sprites.Clear();
            ComputeTotalVertices();

            ShapeDescriptor final = PreCompute();

            if (vbTotal == 0)
                return;

            if (vertexBuffer == null)
            {
                vertexBuffer = new VertexBuffer(
                     typeof(CustomVertex.TransformedColored),
                     vbTotal,
                     UI.Device,
                     Usage.Dynamic | Usage.WriteOnly,
                     CustomVertex.TransformedColored.Format,
                     Pool.Default
                     );
            }
            if (indexBuffer == null)
            {
                indexBuffer = new IndexBuffer(
                    typeof(int),
                    ibTotal,
                    UI.Device,
                    Usage.Dynamic | Usage.WriteOnly,
                    Pool.Default);
            }

            GraphicsStream vbStream, ibStream;

            vbStream = vertexBuffer.Lock(0, 0, LockFlags.Discard);
            vbStream.Write(final.Vertices);
            vertexBuffer.Unlock();

            ibStream = indexBuffer.Lock(0, 0, LockFlags.Discard);
            ibStream.Write(final.Indices);
            indexBuffer.Unlock();

 		}

ive made a simple application before that writes down all of the device caps settings so that i could compare them from different pc's and make solutions according to that. and ive noticed that the output from my sister's pc has something that might be involved in this problem: SupportsTransformedVertexVideoMemory: False is that it? if so, how can i solve it? just for a record, this is how the menu should look like (my pc): http://shy.eastforce.net/pics/menu1.JPG and this is from my sis' http://shy.eastforce.net/pics/menu2.JPG any ideas? :( thanks in advance.