st: error message in biprobit

["Gandelman, Nestor" <gandelman@ort.edu.uy>]

Dear statlisters,
I'm estimating several bivariate probit model using the biprobit
command.
In some of them I recieve the follwing error message:

"initial values not feasible"

Does this mean that I can't estimate those models?
Does anybody know how this can be solved?

Thanks,
                        Nestor

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