Synthesis Error:loop statement with empty body is not permit

I'm trying to update parallella-fpga project to use the latest Vivado. After updating Xilinx ip, I final able to Open Block Design. But when I try to Synthesis the project. I got this error:
[Synth 8-2300] loop statement with empty body is not permitted in this mode of verilog ["parallella/parallella-fpga/7020_hdmi/7020_hdmi.srcs/sources_1/bd/elink2_top/ipshared/c2c9/src/oh_mux.v":24]
I'm not expert of verilog/Synthesis. Does anyone know how to solve this problem?
Thanks,
Min
[Synth 8-2300] loop statement with empty body is not permitted in this mode of verilog ["parallella/parallella-fpga/7020_hdmi/7020_hdmi.srcs/sources_1/bd/elink2_top/ipshared/c2c9/src/oh_mux.v":24]
I'm not expert of verilog/Synthesis. Does anyone know how to solve this problem?
Thanks,
Min