求助各位，mplus 测量模型运行结果中提示如下警告，请教大家是什么意思？谢谢。要如何处理？
THE MODEL ESTIMATION TERMINATED NORMALLY

     THE STANDARD ERRORS OF THE MODEL PARAMETER ESTIMATES MAY NOT BE
     TRUSTWORTHY FOR SOME PARAMETERS DUE TO A NON-POSITIVE DEFINITE
     FIRST-ORDER DERIVATIVE PRODUCT MATRIX.  THIS MAY BE DUE TO THE STARTING
     VALUES BUT MAY ALSO BE AN INDICATION OF MODEL NONIDENTIFICATION.  THE
     CONDITION NUMBER IS      -0.318D-17.  PROBLEM INVOLVING PARAMETER 31.

     THIS IS MOST LIKELY DUE TO VARIABLE SH1 BEING DICHOTOMOUS BUT
     DECLARED AS CONTINUOUS.


     WARNING:  THE LATENT VARIABLE COVARIANCE MATRIX (PSI) IS NOT POSITIVE
     DEFINITE.  THIS COULD INDICATE A NEGATIVE VARIANCE/RESIDUAL VARIANCE FOR A
     LATENT VARIABLE, A CORRELATION GREATER OR EQUAL TO ONE BETWEEN TWO LATENT
     VARIABLES, OR A LINEAR DEPENDENCY AMONG MORE THAN TWO LATENT VARIABLES.
     CHECK THE TECH4 OUTPUT FOR MORE INFORMATION.
     PROBLEM INVOLVING VARIABLE F2.