kernel compilation error

I want to run linux on niosII system and the development board is altera stratix gx. There are three flash in gx development board. When I compile the kernel, the errors happen as this

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Kind Description Resource In Folder Location

Error *** [_all] Error 2 kernel_1s40

Error *** [arch/nios2nommu/kernel/asm-offsets.s] Error 1 kernel_1s40

Error *** [arch/nios2nommu/kernel/asm-offsets.s] Error 2 kernel_1s40

Error# error Sorry,you dont have na_stratix_gx_epc16_kernel or na_stratix_gx_epc16_kernel_end defined in the core.[/cygdrive/d/altera/nios/bin/eclipse/plugins/com.microtronix.nios2linux.kernel_0.1.5/linux-2.6.x/arch/nios2nommu/kernel/asm-offsets.c] kernel_1s40 line 144

Error error: `na_stratix_gx_epc16&#39; undeclared (first use in this function)[/cygdrive/d/altera/nios/bin/eclipse/plugins/com.microtronix.nios2linux.kernel_0.1.5/linux-2.6.x/arch/nios2nommu/kernel/asm-offsets.c] kernel_1s40

Error error: (Each undeclared identifier is reported only once[/cygdrive/d/altera/nios/bin/eclipse/plugins/com.microtronix.nios2linux.kernel_0.1.5/linux-2.6.x/arch/nios2nommu/kernel/asm-offsets.c] kernel_1s40

Error error: `na_stratix_gx_epc16_end&#39; undeclared (first use in this function)[/cygdrive/d/altera/nios/bin/eclipse/plugins/com.microtronix.nios2linux.kernel_0.1.5/linux-2.6.x/arch/nios2nommu/kernel/asm-offsets.c] kernel_1s40[/b]

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stratix_gx_epc16 is one of the three flashes in my nios sytem. What&#39;s wrong and how to correct it? Thank you !