Variable not found even it is defined correctly and there are not missing values

[John Winter]

Hello all,

I have a question about the following code:

***** STOCHASTIC FRONTIER ANALYSIS
************************************************** ***************************
frontier ltc `vx', cost technique(dfp)
************************************************** ***************************
***** PREDICTED TOTAL COSTS, DERIVED AVERAGE AND MARGINAL COSTS
************************************************** ***************************
predict pltcx, xb
gen tocx = exp(pltcx)*ip3 // *ip3???
gen acx = tc/q // tocx?
#delimit ;
gen mcx = acx*(_b[lq]+_b[lqsq]*lq+_b[lwllq]*lip1+_b[lwklq]*lip2
-(_b[lwllq]+_b[lwklq])*lip3) ;
#delimit cr
pwcorr tc tocx
count if tc > tocx
sum tc tocx mcx
************************************************** ***************************
***** LOCAL VARIABLE LIST 1 (w/o CONTROLS)
************************************************** ***************************
#delimit ;
local v1 lwl lwk lwlsq lwksq lwllwk lo1 lo2 lo1sq lo2sq lo1lo2
lwllo1 lwllo2 lwklo1 lwklo2 lnp1 lnp2 lnnp2i ;
#delimit cr


I got the following (see attached file): "[lq] not found"

But lq is in the dataset defined and there are no missing values or negative values

Can smb support pls here?

Thanks a lot!