Starting Values for a non-linear regression

#1
Hi I am trying to get the starting values for non-linear regression of a data set that follows a weibull function. I tried to do the OLS regression of this equation:

log(log(1-F(t)))=-Beta(log(lambda))-Beta(log(t)) to get the starting values.

The only problem is that F(t) is greater than 1 which leads taking a log of a negative values (not possible.) Anyother suggestions on getting these starting values.
 

Dason

Ambassador to the humans
#3
Can you provide more info on what you're doing? If F(t) is what it normally stands for then it can't be greater than 1.