word and long access of SDRAM

I am working with samsung 2410 and k4S561632A 256M SDRAM we are using SDRAM only as 128M With trace32 we have confirmed word access of SDRAM works right. Setting display format as 16 bit and writing word at trace32 termial works right. But when we set display type long, and writing 32 bit data, it fails. Lower word is repeated in upper word. but we have anyway succeeded in word access, we have passed the situation. But when I have download bootloader and debugging, I have found 32 bit instruction in SDRAM displays same situation. lower word of instruction is same as upper word. and CPU malfunctions. code in flash works right. I have no idea why this situation occurs. I even have no idea if this is h/w or s/w problem. I have tried some memory controller setting, but it remains the same. Please let me solve this problem thanks.