5002 Error-control Motor Stepper

I tried to creat a Labview program to controll 4 motor steppers at the same time, but I always meet the 5002 error although i run 1 or 4 at one. I tried to fix but it's hard for me. I have uploaded LIFA with 9600 baud rate at the low version (i have tried with 115200 before), have checked the port, have done any thing possible but nothing happen. 5002 is still 5002. I don't need sleep, i need an answer. Pls help me. 
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