This issue is with how the GraphPak library works on Windows 64-bit platforms, and it applies to all GUIs using the GraphPak library (e.g., CIC, FIR etc.).
The graphing data sets are being passed from Tcl to GraphPak correctly, but they are not being displayed on the Windows 64bit.
This problem has been fixed in the latest 10.1 Service Pack available at:
http://www.xilinx.com/support/download/index.htmThe first service pack containing the fix is 10.1 Service Pack 1.