st: Unknown function () error.

["Vimalanand S. Prabhu" <prabhu@unc.edu>]

Hi

I am new to ml command. I am getting an error: Unknown	function (), when 
I run the following code for negative binomial count model. Is there any 
obvious error in the code which I seem to miss out.

The L function is -exp(lambda.ui).(lambda.ui)^yi/(yi)!

program define nbreg2
args lnf theta uu
quietly replace `lnf' = -exp(`theta')#`uu' + $ML_y1#(`theta'+ln(`uu')) - 
lnfact($ML_y1)
end
ml model lf nbreg2 (jdemh=price eff) ()
ml check
ml maximize

Thanks,

Prabhu
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/