Compile the DDR2 SDRAM

hello, girls and guys, i met a problem with the DDR2 SDRAM compilation.

first i built a small program with the SOPC Builder, and it contains a Nios II/standard, a DDR II SDRAM IP, and a DMA Controller, a PLL, two on chip rams(one is 128K*32b, the other is 64K*32b), a Jtag_Uart, and a Timer. After the suessfullly generation with the SOPC Builder, i used the Quartus II to do the compilation, in the fit procedure, it pops up some error: seems the memory is out of use, so i cutted the DMA, and minimized the on chip ram, just left the DDR II and Nios, also JTAG, and recompiled, but this time, at the beginning of the compilation, the Quartus poped up the following error message in another window.

the detailed information follows:

*** Fatal Error: Module: quartus_map.exe Exception: Access Violation

0x132E8 : qcu_read_acf_assignment + 0x107C (comp_qcu)

0xA936 : (quartus_map)

0x94EF : qexe_get_command_line + 0xE1 (comp_qexe)

0xB362 : qexe_run_tcl_option + 0x4E2 (comp_qexe)

0xB3AF : qexe_standard_main + 0x14 (comp_qexe)

0x2A32B : msg_exe_main + 0xDB (CCL_MSG)

0x9D4D : (quartus_map)

0x256D9 : BaseProcessInitPostImport + 0x2E2 (kernel32)

0x83C5FFFF: MEM_MANAGER::s_quartus_memory_counter + 0xFFD6EFC2 (MSVCR71)

End-trace

has anyone met the similar problem before? or has someone used the DDR 2 before?

i really want to listen your advice and ideas.

Expecting!!

thanks in advance!!