st: Error message

["Fred Dzanku" <fdzanku@gmail.com>]

Dear All, 
I estimated the following SUR model:
	qui: bootstrap, rep(20) cl(clust) str(dist) seed(10031976)  ///
		nodots: sureg (pgap_h $flbpr) (psev_h $flbpr)

after which I requested for the following:
	margins, eyex(*) predict(equation(pgap_h))

which worked fine but when I tried this for the second equation I get an
error message which reads as follows:
	"could not calculate numerical derivatives -- discontinuous region
with missing values encountered
	r(459);"
This happens whether or not I use the bootstrap option. It also happens with
mvreg. This however does not occur when I estimate the equations
individuation. I tried introducing the variables one after the other to see
if some particular variable(s) might be responsible and found that out of
the 24 variables contained in $flbpr 14 of them work fine but when I
introduce any of the other 10 then the error message comes up. I've check
these variables and don't seem to find exactly what the problem is. Can
anyone help please? 
Fred


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