Stepper Motor Configuration problem

I tried with 2 stepper motors NEMA 17 and 2 DM420A Controller driver and have the same problem where the stepper motor trembles and can move in.any direction in an alternate way. 
My wirings are A+ A- B+ B- to blue, red, green, black of the stepper motor and DC+ to the 12 volts power and DC- to GND of the same power. The signals PUL to the PIN 2 of the BOB DB25-1205 and DIR to the PIN.3 of the BOB. And +5V to the 5 volts power and ENBL to the grownd of the same.power.  Setting 1,2. 4,5,6,7 ON, 4, OFF      

X AXIS Configuration  

You forgot the visual of your driver step setting (SW1~7). (edit: ah. just noticed the "Setting 1,2. 4,5,6,7 ON, 4, OFF" part.)

When you say "tremble", you mean as in resonance or the motor direction is eratic? I.e. resonance, low cost steppers/drivers are notorious for that, particularly in their 50~150Hz range (natural freq). Before upgrading for half- decent motion I had my mill enclosure sheet metal rattling and screaming for help each and every accel/decel, I swear it sounded like a freight train...

Try: 1:OFF, 2:OFF, 3:OFF,  4:OFF, 5: OFF, 6:OFF, 7:ON. And set this to 8.0 in pconf.
If you still have excessive resonance, your steppers/drives are best in the bin. Re-equipped!

Thanks you both.
The problem was with the step time and dir stuff and the base period.
Now it doesn't trembles anymore and the movement is continous. I have to adjust it to the best numbers but you were right.
Great Job
Thanks you both