Varification failed when downloading to SRAM

Hi...

I am New to NIOS II...

I am using a custom made NIOS II Board (CYCLONE III).

I have the following problems when downloading .

1. I am able to download a program to onchip memory but can't to SRAM connected to my board.

When downloading to SRAM NIOS II IDE shows Varification Failed.

2.So I wrote one simple program to check the SRAM.

I am able to acess SRAM.....My H/W details about the SRAM is as follows

Size:---512kx16

[A19....A1] of sopc builder is connected to [A18....A0] of SRAM

Using the following API I wrote to RAM

IOWR_16DIRECT(sram_base, 0, 0x8748);

tx1=IORD_16DIRECT(sram_base,0);

I am getting Correct value in tx1

3. When I wrote to sram_base+2

when read back it is showing FF only.

at sram_base+4 correct and the above order is repeating......Why?

4.In Debug mode NIOS II IDE I saw each location in sram is 8 bit wide only...

is it possible to view in 16bit mode?

5.In my RAM connection BHE and BLE is Connected permanently to Ground(always enabled).I am not Using BHE and Ble from NIOS......

6. Please explain How the nios is accessing 16bit data from the memory

Please clear my doubt...........