st: nl nonlinear regression

[ssteffen <ssteffen@princeton.edu>]

Dear Statalistserv,

for the nonlinear regression I am trying to run, I keep getting:
error #198 occurred in evaluating expression
invalid syntax
starting values invalid or some RHS variables have missing values

I know that my RHS variables are fine, because I can run a normal 
regression with them without a problem.
I am not so sure what the "starting values invalid" could mean.
Here is the equation I am trying to estimate:

return local eq "`lyt' = 
(1-exp(-25*{b0}))*({b1}/(1-{b1}-{b2}))*`lsk'+(1-exp(-25*{b0}))*({b2}/(1-{b1}-{b2}))*`lsh'-(1-exp(-25*{b0}))*(({b1}+{b2})/(1-{b1}-{b2}))*`lngd'+exp(-25*{b0})*`ly0'"

Thanks for help,

Sebastian

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