我用的spartan 6的片子，ISE12.2，BSCAN可以找到器件并且下载程序，但是在用ChipScope时出现下面的错误

请教各位，谢谢！

INFO: ChipScope Pro Analyzer Version: 12.2 M.63c (Build 12200.10.179.704)

COMMAND: open_cable
INFO: Attempting to connect to an existing server.
INFO: Successfully opened connection to server: localhost:50001 (localhost/127.0.0.1)
ERROR: Communication with server failed: java.nio.BufferOverflowException
ERROR: client/server communication not open.
ERROR: Failed detecting JTAG device chain
ERROR: client/server communication not open.
ERROR: Opened Xilinx Platform USB Cable but failed to detect JTAG Chain.
INFO: Trying to open Xilinx Platform USB Cable on port USB2
ERROR: client/server communication not open.
ERROR: Internal Error - runCseThread method() failedjava.lang.ArrayIndexOutOfBoundsException: 0
ERROR: Communication with server failed: java.lang.ArrayIndexOutOfBoundsException: 0