Warning (15610): No output dependent on input pin

The reason is simple and can be seen in the below always block. There are multiple assignments to each x_bus_out, but only the last takes place.

always @ (TAU_A, TAU_B, TAU_C, TSR_A, TSR_B, TSR_C, TR_A, TR_B, TR_C, tau_w2, tsr_w2, tr_w2)
begin
	if(TAU_A == 1)
	begin
		A_bus_out = tau_w2;
	end
	else
	begin
		A_bus_out = 12'hzzz;
	end
	if(TAU_B == 1)
	B_bus_out = tau_w2;
	else
	B_bus_out = 12'hzzz;
	
	if(TAU_C == 1)
	C_bus_out = tau_w2;
	else
	C_bus_out = 12'hzzz;
	
	/////////////////////////
	
	if(TSR_A == 1)
	A_bus_out = tsr_w2;
	else
	A_bus_out = 12'hzzz;
	
	if(TSR_B == 1)
	B_bus_out = tsr_w2;
	else
	B_bus_out = 12'hzzz;
	
	if(TSR_C == 1)
	C_bus_out = tsr_w2;
	else
	C_bus_out = 12'hzzz;
	
	//////////////////////////
	
	if(TR_A)
	A_bus_out = tr_w2;
	else
	A_bus_out = 12'hzzz;
	
	if(TR_B)
	B_bus_out = tr_w2;
	else
	B_bus_out = 12'hzzz;
	
	if(TR_C)
	C_bus_out = tr_w2;
	else
	C_bus_out = 12'hzzz;
end	

You probably meaned to write (and similar for the other outputs):

  if(TAU_A == 1)
    A_bus_out = tau_w2;
  else if(TSR_A == 1)
    A_bus_out = tsr_w2;
  else if(TR_A)
    A_bus_out = tr_w2;
  else
    A_bus_out = 12'hzzz;

Thank you so much FvM. Yes, you are right.

The warnings disappeared and it replaced by new errors that do not make sense to me.

I connected the same wire to several blocks and I got these errors.

It shows only for these two blocks that mentioned below. I did the same for others, but it does not show as an error.

I attached the new project and thank you again for your time.

Error (12014): Net "tr_w1[11]", which fans out to "FU_reg:TR_reg_Inst|in0[11]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[23]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[11]"

Error (12014): Net "tr_w1[10]", which fans out to "FU_reg:TR_reg_Inst|in0[10]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[22]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[10]"

Error (12014): Net "tr_w1[9]", which fans out to "FU_reg:TR_reg_Inst|in0[9]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[21]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[9]"

Error (12014): Net "tr_w1[8]", which fans out to "FU_reg:TR_reg_Inst|in0[8]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[20]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[8]"

Error (12014): Net "tr_w1[7]", which fans out to "FU_reg:TR_reg_Inst|in0[7]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[19]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[7]"

Error (12014): Net "tr_w1[6]", which fans out to "FU_reg:TR_reg_Inst|in0[6]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[18]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[6]"

Error (12014): Net "tr_w1[5]", which fans out to "FU_reg:TR_reg_Inst|in0[5]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[17]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[5]"

Error (12014): Net "tr_w1[4]", which fans out to "FU_reg:TR_reg_Inst|in0[4]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[16]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[4]"

Error (12014): Net "tr_w1[3]", which fans out to "FU_reg:TR_reg_Inst|in0[3]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[15]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[3]"

Error (12014): Net "tr_w1[2]", which fans out to "FU_reg:TR_reg_Inst|in0[2]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[14]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[2]"

Error (12014): Net "tr_w1[1]", which fans out to "FU_reg:TR_reg_Inst|in0[1]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[13]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[1]"

Error (12014): Net "tr_w1[0]", which fans out to "FU_reg:TR_reg_Inst|in0[0]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_mul_1:amz_mul_1_inst|result[12]"

Error (12015): Net is fed by "amz_div_1:amz_div_1_inst|remain[0]"

Error (12014): Net "overflow_sig", which fans out to "FU_reg:TSR_reg_Inst|in0[9]", cannot be assigned more than one value

Error (12015): Net is fed by "amz_add_sub_1:amz_add_sub_1_inst|overflow"

Error (12015): Net is fed by "amz_log_shift:amz_log_shift_inst|overflow"

Error (12015): Net is fed by "amz_arith_shift:amz_arith_shift_inst|overflow"

Error: Quartus II 64-Bit Analysis & Synthesis was unsuccessful. 40 errors, 1 warning

Error: Peak virtual memory: 435 megabytes

Error: Processing ended: Thu Feb 27 10:34:49 2014

Error: Elapsed time: 00:00:02

Error: Total CPU time (on all processors): 00:00:02

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I connected the same wire to several blocks and I got these errors.

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The errors are justified. You can't connect the same net to multiple module output ports. A multiplexer must be connected intbetween to select which output drives the net at a time.