Problem using SDRAM on DE0 board(EP3C16F484C6)

HI,

I am using DE0 EP3C16F484C6 board on Quartus 12.1sp1 webedition. I have successfully generated the design on Qsys and compiled on Quartus. But when I program the design on the board and run hello world program it gives me downloading elf failed though the pins are mapped according to the data sheet.

I am unable to figure out what the problem is. I have attached my qpf, qsf and qsys file. If some one can help me out.