[R] datadist() in Design library

[array chip]

Hi I got an error message using datadist() from Design package:

> library(Design,T)
> dd <- datadist(beta.final)          
> options(datadist="dd") 
> lrm(Disease ~ gsct+apcct+rarct, x=TRUE, y=TRUE)
Error in eval(expr, envir, enclos) : object "Disease" not found

All variables inclduing response variable "Disease" are in the data frame "beta.final", why then "Disease" can not be found? I thought with datadist(), all variables are presented to the model fitting functions. maybe I am wrong?

thanks

John