Truncreg package help

Dear R userers,

I am running truncated regressions with the 'truncreg' package. My sample 
is large (6,000 observations), the data is left-truncated at 1 and the 
left tail of the data is heavily centered at 1. When I am running the 
regression I receive the following error message: 

  Error in optim(par = start[!fixed], fn = logLikFunc, control = control, 
: 
  initial value in 'vmmin' is not finite

From a previous discussion (

http://r.789695.n4.nabble.com/betareg-help-td3350129.html) on a similar 
issue in the betareg function I assume that the error message stems from 
that the estimate of the starting value of the precision parameter is 
negative. However, I do not know how I can take care of this. Thus I would 
be very thankful for any help.

Best regards,
Philipp