Abaqus设置时，好多种边界条件都出现如下错误信息，这是怎么回事？边界条件一般是如何设置才不会出这种错？

***ERROR: The nodes in the Abaqus/Viewer node set "ErrNodeRotNodeNoRotInert"          have no rotary inertia about more than one axis  associated with          them and some rotational degrees of freedom at the nodes are not          constrained. Either rotary inertia must be defined or all of the          rotational degrees of freedom must be constrained. See the message          file for more detailed information.