Problem in Convolutional encoder block

Hey all, I am working on communication design. I am new in simulink so I am getting many problems. I am making transmitter block in Xilinx system generator. I am using convolutional encoder block. I am getting this error

"Error reported by S-function 'sysgen' in 'encoder/Convolutional Encoder1/Subsystem/Constant': An internal error occurred in the Xilinx Blockset Library.

Please report this error to Xilinx (<http://support.xilinx.com)>, in as much detail as possible. You may also find immediate help in the Answers Database and other online resources at http://support.xilinx.com.

Since it is possible that this internal error resulted from an unhandled usage error in your design, we advise you to carefully check the usage of the block reporting the internal error. If errors persist, we recommend that you restart MATLAB."

Can anyone please guide me what to do??

Regards