计算驾驶室结构模态时出现以下错误，是什么意思

*** WARNING # 1121
No SPC data specified for eigenvalue SUBCASE 2.
FREE-FREE boundary condition assumed.
*** INFORMATION # 742
The dependent rotational d.o.f. of this rigid element is removed.
RBE2 element id = 62857
independent grid id = 9654
a dependent grid id = 290
This is because there is no need to constrain the rotational d.o.f. of
any of the dependent grids.
这段什么意思？
***** Warning for eigenvalue subcase 2:
- At some point in the process, an inconsistent inertial count
was found. This implies that some of the calculated frequencies
may be inaccurate, especially the duplicated frequencies.
To avoid this, specify both bounds and keep the bound away
from the currently calculated frequencies.
*** warning *** the rayleigh quotient
x'kx / x'mx for the 1-th eigenvector
does not match the computed eigenvalue
lambda ( 1): -3.43657732493052D-02
x' k x : -3.17497987461738D-02
x' m x : 9.99999999999997D-01
discrepancy : 2.61597450313135D-03
*** warning *** the rayleigh quotient
x'kx / x'mx for the 2-th eigenvector
does not match the computed eigenvalue
lambda ( 2): -2.52264003761536D-02
x' k x : 2.98770863757770D-04
x' m x : 1.00000000000000D+00
discrepancy : 2.55251712399114D-02