R help - Jul 2009 - number of iterations exceeded maximum of 50 using profile

Hi R users and experts:
   I got the following message when I use the profile
   function on a nls models. The nls function converges at 19 interactions,
   but I don't know what I am doing wrong using the "profile"
function.
   "Error en prof$getProfile() : number of iterations exceeded maximum of
50"
   I'm sending the database and the R script.
   abutilon<-read.csv2("abutilon.csv")
   abutilon$hrb_tam<-factor(with(abutilon,paste(herbicida,tam)))
  
modeloNL1<-nls(porcpesoseco~alfa[hrb_tam]*(beta[hrb_tam]*tasa^gamma[hrb_tam]
   /(1+beta[hrb_tam]*tasa^gamma[hrb_tam])),data=abutilon,
                  start=list(alfa=rep(100,6),beta=rep(0.6,6),gamma=rep(-1,6)))
   summary(modeloNL1)
   profile(modeloNL1)
   Thank you for your help.
   Kenneth