[R] Problems with lme4 and cholmod_start

[Lorena Pont-Lezica]

Hello,
I just installed Rv2.13,lme4 v0.999375-40, and matrix 0.999375-50. When I
try to launch lme4 I get the following error message:

> library(lme4)
Error in inDL(x, as.logical(local), as.logical(now), ...) :
  function 'cholmod_start' not provided by package 'Matrix'
Error: package/namespace load failed for 'lme4'

I can't seem to figure out what is wrong and what I should change. I tried
earlier versions of matrix but it did not help. I cannot seem to find the
chomold_start file anywhere...
Your help would be much appreciated, thank you!
Lorena