Error message: “st_matrixcolstripe(): 3300 argument out of range katya(): – function returned error : – function returned error”

this code appears to perform a statistical analysis, involving maximum entropy estimation, on data from multiple years. It calculates weights for observations based on constraints and potentially optimizes a model by iteratively adjusting parameters. This was written by someone else and they are very busy, where do I probe for errors? For your reference, this is what the code for MATA looks like:

 do "$path/gidd programs/Mata Select reweight targets.do"

    ds c1f00-c3m70

    * Call Mata Function

        mata: katya("r(varlist)")   // The Katya Function 

        drop const

        svmat Q0, names(matcol)

        local f_varlist ""

        foreach var of varlist c1f00 - c3f75 {

            capture confirm variable Q0`var'

            if !_rc {

                local f_varlist "`f_varlist' `var'"

            }

            else {

                drop `var'

            }

        }


        drop Q0*

        if "`foreign'"!="" matrix define Y = (Y  `foreign')

        svmat Y, names(col)

        rename c1 const

    if "`foreign'"!="" {

            merge 1:1 idh using `foreigndb'

            drop _merge

            noi di "Maxentropy for year `a'"

            noi di "The constraint matrix for year `a'"

            matrix list const`a'

            noi di "`country'"

            noi di "maxentropy const `f_varlist' foreign, prior(`iweights') generate(newwgt) total(`tsumpop`a'') "          

            cap maxentropy const `f_varlist' ___foreign, prior(`iweights') generate(newwgt) total(`tsumpop`a'') 

            if !_rc {

            gen newiwgt = newwgt/hhsize

            keep `id' newiwgt

            clonevar idh_merge = `id'

            sort idh_merge

            tempfile max`a'

            save `max`a'', replace

            local a = `a' + `stp'

            }

            else {

                noi di "Convergence not achieved at alpha: " $sc_alpha

                global sc_alpha = $sc_alpha * 10

                noi di ""

                noi di "New alpha: " $sc_alpha

            }   

    }


    if "`foreign'"=="" {

            noi di "Maxentropy for year `a'"

            noi di "The constraint matrix for year `a'"

            matrix list const`a'

            noi di "`country'"

            noi di "maxentropy const `f_varlist' , prior(`iweights') generate(newwgt) total(`tsumpop`a'') "         

            cap maxentropy const `f_varlist' , prior(`iweights') generate(newwgt) total(`tsumpop`a'') 

            if !_rc {

            gen newiwgt = newwgt/hhsize

            keep `id' newiwgt

            clonevar idh_merge = `id'

            sort idh_merge

            tempfile max`a'

            save `max`a'', replace

            local a = `a' + `stp'

            }

            else {

                noi di "Convergence not achieved at alpha: " $sc_alpha

                global sc_alpha = $sc_alpha * 10

                noi di ""

                noi di "New alpha: " $sc_alpha

            }   

    }       


restore

}



  use `base', clear

forval a = `iyear'(`stp')`tyear' {

    clonevar idh_merge = `id'

    sort idh_merge

    merge m:1 idh_merge using `max`a''

    tab _merge

    drop _merge

    sort idh_merge

    drop idh_merge

    gen double `generate'`a' = newiwgt

    drop newiwgt

}

    }

    end

The do file called above has the following:
version 12
clear mata

 mata:
 void katya(string scalar variables)
 {
    varnames=tokens(st_global(variables))
        x=st_data(., ("c1f00 - c3m70"))
        y=st_data(., "const")

        submat = select(y, rowmissing(y):< $sc_alpha)
        z = select(x',submat:>= $sc_alpha)'
        q = select(submat,submat:>= $sc_alpha)
        colnames=select(varnames',submat:>= $sc_alpha)
        colnames=J(rows(colnames),1,""), colnames
        q0        = select(q ,rowsum(z'):>= $sc_alpha)

        colnames0 = select(colnames,rowsum(z'):>= $sc_alpha)
        qnull   = select(q ,rowsum(z'):< $sc_alpha)'
        colnull = select(colnames, rowsum(z'):< $sc_alpha)  

        q0_ = q0'
        st_matrix("Q0",q0_)
        st_matrixcolstripe("Q0", colnames0)
        st_matrix("Y", q0)  
}
end