st: too large standard errors of marginal effects after multinomial logitmodel

[dpeng@umsis.miami.edu]

When I calculate the marginal effects after multinomial logit model using the 
command "mfx compute, predict (outcome(1))", Stata gives me very large standard 
errors and all p values are equal to 1. Dose anyone know the reason of this 
problem and how to solve it? Many thanks.
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