[R-sig-ME] env() error message

[array chip]

I am following examples of the lme4 draft book. 

> fm1 <- lmer(Yield ~ 1 + (1|Batch), Dyestuff)
> env(fm1ML)$Lambda
Error: could not find function "env"

what went wrong here? Maybe env() function is from some special package that I 
didn't attach?

Thanks

John

> sessionInfo()
R version 2.10.1 (2009-12-14) 
i386-pc-mingw32 

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] nlme_3.1-96        lme4_0.999375-33   Matrix_0.999375-39 lattice_0.18-3    

loaded via a namespace (and not attached):
[1] grid_2.10.1  tools_2.10.1