estimation problem-there are not results

[ngoclansg]

Dear All

I am doing my graduate thesis and now I have this estimation problem. :(

when run estimation equation, I receive this message:

WARNING: Singular covariance - coefficients are not unique

Covariance matrix computed using second derivatives

And there are not results (NA) of standard error, z-statistics, prob.

I would be very grateful that you would help me with this problem. I thank you a thousand times.

Yours faithfully

Ngoc Lan

[startz]

You either have near perfect multicollinearity or a problem with the starting values in a nonlinear estimation...most likely.

[ngoclansg]

thank you a lot for your advice.