Nios ii de2

I am a beginner and NOSII Quartus I operate Altera DE2, I wanted to use the SD card (memory card from my Altera DE2) board for a project.

after sending the architecture of the example that comes with the CD named DE2_SD_Card_Audio, I encountered a problem while sending the executable file (. sof), and here is the error message that is displayed "launching XXX2013Nios II Hardware configuration has Encountered a problem. Elf downloading process failed". Another alternative display shows that there is a problem between address "Verifying failed 0X6000000 address and 0X600FFFF Between", these addresses correspond to memory addresses 2 (RAM U2).

NB: the file. Sof that comes with the example works fine, but when I compile the example and brings ALTERA gives me another SOF File. Sof gives the problem mentioned before.

Thank you for your suggestions and support to avoid this problem.