Warning: No Clocks Defined in Design

I am facing similar problems.

I am trying to use the clocks provided on DE1 board from TerAsic (24MHz, 27MHz & 50MHz).

But My code doesn't work.

This is my code:

module LedBlink(CLOCK_24, LEDR);

input[1:0] CLOCK_24;

output [7:0] LEDR;

wire ovf;

reg out;

reg en, clk, clr;

reg[31:0] maxClks;

reg[7:0] div;

initial

begin

clk = 0;

div = 0;

out = 0;

maxClks = 1000000;

# 10 en=1;

# 10 clr=1;

# 20 clr = 0;

end

always @(posedge CLOCK_24[0])

begin

div = div + 1;

if(div == 24)

begin

clk = ~clk;

div = 0;

end

end

always @(posedge ovf)

begin

out = ~out;

end

assign LEDR[0] = out;

DelCtr del (ovf, en, clk, clr, maxClks);

endmodule

I had made use of the CLOCK_24 pin as a clock by using always construct.

But still I get the warning in quartus "No Clock Source Defined in Design".

Pls Help