Dear Stata users,

I am performing the following MI code,
HTML Code:
mi impute chained (logit, augment)a4_0 a5_1_0 g4_a a4_12 a5_1_12 a4_24 a5_1_24 a4_36 ///
      a5_1_36 a4_48 a5_1_48 a4_60 a5_1_60 (ologit, augment)a1_0 a1_12 a1_24 a1_36 a1_48 ///
      a1_60 bmi_c_0 bmi_c_12 bmi_c_24 bmi_c_36 bmi_c_48 bmi_c_60 (mlogit, augment)g3 g8 (ologit, ascontinuous)a2 ///
   = age sex cluster, add(50) rseed (53421) savetrace(trace1,replace)
However, I got the following error message;
HTML Code:
Performing chained iterations ...
mi impute: VCE is not positive definite
    The posterior distribution from which mi impute drew the imputations for a5_1_60
    is not proper when the VCE estimated from the observed data is not positive
    definite.  This may happen, for example, when the number of parameters exceeds the
    number of observations. Choose an alternate imputation model.
error occurred during imputation of a4_0 a5_1_0 g4_a a4_12 a5_1_12 a4_24 a5_1_24 a4_36
a5_1_36 a4_48 a5_1_48 a4_60 a5_1_60 a1_0 a1_12 a1_24 a1_36 a1_48 a1_60 bmi_c_0
bmi_c_12 bmi_c_24 bmi_c_36 bmi_c_48 bmi_c_60 g3 g8 a2 on m = 1
Please help me to sort this issue.