weights in lmer_0.999375-23

Hi, Prof. Bates (and others),

It seems that in the latest version of lme4 from CRAN or R-forge the 
weights argument does not work:

library(lme4)
set.seed(1)
w <- abs(rnorm(nrow(sleepstudy)))
fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)
fm2 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy, weights = w)
Error in mer_finalize(ans, verbose) :
   Calculated PWRSS for a LMM is negative
 > sessionInfo()
R version 2.7.1 (2008-06-23)
i386-pc-mingw32

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United 
States.1252;LC_MONETARY=English_United 
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

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

other attached packages:
[1] lme4_0.999375-23   Matrix_0.999375-12 lattice_0.17-12

loaded via a namespace (and not attached):
[1] grid_2.7.1  tools_2.7.1