I need your help regarding the code for multilevel modelling that I am referring to but it is not running from couple of days. The outcome variable is height whose variation I am about to see at individual, household, district and the state level. The code that I am running is unable to get processed as it is showing the error of "error obtaining the robust variances".
I am attaching the code which I am using for your consideration.
I shall be obliged if you can please help me out with this.

Code:
setmaxiter 100
xtmixed ht wt v212 i.v149 WEIGHT_FOR_AGE [pweight = v005] || new_code: GROWTH GROWTH_RATE || sdistri: dist_lit dist_urban || v002: i.v190 i.v025, nostderr