Problem with Pixel_Buffer_DMA and SDRAM

Have you tried setting the reset/exception vector to on-chip memory? I had this issue also trying to implement a frame buffer for the project I'm working on now. (BTW if you get the back buffer to work using the pixel_buffer_dma driver please let me know, I've been having trouble with it). I found reading/writing for the SDRAM worked when I had on-chip memory for reset/exception but when I changed it to SDRAM, it no longer worked. Let me know if this helps.