Errors in ABAQUS

Hi every one,

I'm new in ABAQUS and trying to do wave propagation by using it. I'm using ABAQUS 6.12-3

In a cantilever beam I'm using explicit C3D8R elements by a dyamic pulse load. But I got this error:

 DEGREE OF FREEDOM 11 AND AT LEAST ONE OF DEGREES OF FREEDOM 1 THRU 6 MUST BE ACTIVE IN THE MODEL FOR *DYNAMIC TEMP-DISP. CHECK THE PROCEDURE AND ELEMENT TYPES USED IN THIS MODEL.

The only output which I specified for it, is displacement and velocity in the tip of the beam as a history output request.

Would you please let me know what should I do to fix it. I checked my model several time and I couldn't find what's wrong with it. Also I wtched this video in youtube and followed it step by step and again I got the same error:

http://www.youtube.com/watch?v=AhLNmaqCY0Y

It would be the most kind of you to let me know about it.