Crossbararray in Veriloga with for loop

Hello, cadence beginner here.

I want to create a crossbararray in Veriloga with two for loops, but I get the errormessage from the parser: 

 ERROR (VACOMP-2259): "for<<--? (i = 1; i < `size; i = i + 1) begin :
        gen_loop_i"

here is the code:

`define size 4

module crossbar_array_4x4_crossbar_schematic ( I, V );

output    [`size:1]I;

input    [`size:1]V;

genvar i,j;

generate
for(i = 1; i < `size; i = i + 1) begin : gen_loop_i
    for(j = 1; j <= `size; j = j + 1) begin : gen_loop_j
        JART_VCM_2 'i'_'j' ( V[j] , I[i] );
    end
end
endgenerate

endmodule

the VCM module definition is included in the file as well as the constants.vams and disciplines.vams