st: Problems with -ssm

["paolo.dibetta@fastwebnet.it" <paolo.dibetta@fastwebnet.it>]

I am trying to run a sample selection model for count data

pages is the count data variable
attract is an indicator, that makes the sample selection, 
when =1 I have pages, when =0 pages is missing

I am rying to run -ssm, downloaded on from ssc, written by Alfonso Miranda & Sop
hia Rabe-Hesketh
-ssm is a wrapper for gllamm to estimate Endogenous-Switch & Sample Selection Co
unt, Binary & Ordinal Response Regression by maximum likelihood using adaptive q
uadrature. It needs STATA 9.1. 

I run the following model in STATA 10 (I have installed -gllamm):

.ssm pagesm t banner posters qrbillboard qrmagazine qrnewspaper qrnonewspaper, s
witch(
> attract= lag1visitors lag2visitors) selection family(poisson) link(log) robust

I get the following error:
qrbillboard not found
r(111);

or else I get

posters not found
r(111);

and so on.
Sometimes I get
variable id not found

or
attract ambiguous abbreviation
or
variable __000002 not found

or

initial vector: matrix must be dimension 14
(error occurred in ML computation)
(use trace option and check correctness of initial model)
equation id1_1l not found
r(111);

or
variable end not found
equation id1_1l not found
r(111);


I cannot figure out what it is going on.
I will greatly appreciate any help

Best
Paolo Di Betta
University of Palermo 

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