de2 ,flash programmer help!

when i use flash programmer in ide, a errer is given:

the associated NiosII system library poject fo rght application project is refercing a non-existent sopc buider system file. please select the application project and select project->properties->Asociated system library to choose a different system.

i was taught that, de2 is not a standard board, so i have to creat a new flash programmer description for my board by mk_target_board in sdk, as i tryed ,the following response occured,

[SOPC Builder]$ mk_target_board --name=DeviceSopc --family=CycloneII --clock=50

--index=1 --buffer_size=16384 --class=DeviceSopc_Flash_Programmer

Make Target Board version 1.01

Switch summary:

Board name: "DeviceSopc"

Board class: DeviceSopc_Flash_Programmer

Device family: "Cyclone II"

Clock frequency: 50000000hz

Payload buffer size: 16384 bytes

ERROR:

d:/altera/kits/nios2_51/bin/create-board.pl 1279 CALLED (main)

d:/altera/kits/nios2_51/bin/create-board.pl 99 CALLED (cb_setup_directories)

d:/altera/kits/nios2_51/bin/create-board.pl 511 CALLED (europa_utils::find_com

ponent_dir)

/cygdrive/d/altera/quartus51/sopc_builder/bin/europa/europa_utils.pm 2016 CAL

LED (europa_utils::ensure_class_ptfs) WHERE

'get_class_ptf and ensure_class_ptfs must be called with g{system_directory}' OC

CURRED on /cygdrive/d/altera/quartus51/sopc_builder/bin/europa/europa_utils.pm 1

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