xps新建工程下载问题 朋友, between, Error, devices

ppzhy

INFO:iMPACT:1777 -
   Reading d:/Xilinx/10.1/ISE/virtex4/data/xc4vsx25.bsd...
INFO:iMPACT:501 - '1': Added Device xc4vsx25 successfully.
INFO:iMPACT:1777 -
   Reading d:/Xilinx/10.1/ISE/acecf/data/xccace.bsd...
INFO:iMPACT:501 - '1': Added Device xccace successfully.
ERROR:iMPACT:1062 - Can only assign files to devices between positions 1 to 2
make: *** [download] Error 1
Done!
不知道是什么问题，希望哪位朋友可以帮忙解决，先谢了