boxcox error

[gx2144]

  ODS GRAPHICS OFF;

222  ODS GRAPHICS ON;
223   PROC TRANSREG DATA = work6 TEST;
224   MODEL BOXCOX(VT_ln) = IDENTITY(y1p_vs01A11 weight_kg y1p_G_AGE );
225   RUN;

ERROR: 187 invalid values were encountered while attempting to transform
       variable VT_ln.
WARNING: Ordinary missing values were found or an UNTIE transformation or
         the UNTIE= option was specified.  The utility of the hypothesis
         tests are dubious since one parameter must be estimated for each
         of these values.  If you really want to do this, ensure that no
         observations are duplicated -- combine duplicate observations and
         use a FREQ statement.  If you do not, the parameter count may be
         too large and the tests overly conservative.  However, it is best
         to avoid this situation altogether.

 Can someone help with the warning here? What should I do with my response variable?

[Rick_SAS · Accepted solution]

There are two things going on.

The ERROR is because 187 observations for the variable VT_ln are negative or 0. 

The WARNING is because the VT_ln has missing values.

The WARNING is discussed in the doc. 

For more discussion, see this previous thread.