R help - Apr 2015 - calculate Cy0 with qpcR package when fitting is failed

Dear all,
i am trying to calculate the Cy0 from a series of PCR runs in the
384-well. I can create the regression model using the modlist
function:
   ml<-modlist(
      obj,
      cyc = 1,
      model = l4,
      norm = "FALSE",
      remove = "none"
    )

where obj is the dataframe with the fluorescence data and ml is the
resulting vector with 384 elements, but when i try to create the Cy0
values i get the error:
> Cy0(ml, plot = "FALSE")
Error in seq.default(MIN, MAX, by = DIVS) :
  'from' cannot be NA, NaN or infinite


I reckon that this is due to failed amplification data but i don't
know how to screen the function from these abnormal values. when i run
the modlist with arguments remove = "fit" i get the 372 elements but
Cy0 returns the same error.

How can i overcome this issue?
Many thanks,
Luigi