lme4 at flexLambda Error

Furst of all, thank You.
As you request this is my session info.
Best

sessionInfo()

R version 3.0.2 (2013-09-25)
Platform: i386-w64-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=Italian_Italy.1252  LC_CTYPE=Italian_Italy.1252   
[3] LC_MONETARY=Italian_Italy.1252 LC_NUMERIC=C                  
[5] LC_TIME=Italian_Italy.1252    

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

other attached packages:
[1] lme4_2.0     Rcpp_0.11.3  Matrix_1.1-2

loaded via a namespace (and not attached):
[1] grid_3.0.2      lattice_0.20-29 MASS_7.3-35     minqa_1.2.2    
[5] nlme_3.1-119    nloptr_1.0.4    splines_3.0.2