[R] CRAN versions of lme4/Matrix don't appear to work with R 2.1.1

[White, Charles E WRAIR-Wash DC]

I am currently using R 2.1.1 under Windows and I do not seem to be able
to load the current versions of lme4/Matrix. I have run
'update.packages.' I understand this is still experimental software but
I would like access to a working version.

Thanks.

Chuck

R Output:

> library(lme4)
Loading required package: Matrix
Error in lazyLoadDBfetch(key, datafile, compressed, envhook) : 
        ReadItem: unknown type 241
In addition: Warning messages:
1: package 'lme4' was built under R version 2.3.0 
2: package 'Matrix' was built under R version 2.3.0 
Error: package 'Matrix' could not be loaded
>