lme4 error after Matrix update

Dear all,

after recently updating my R-packages I am unable to work with lme4, 
since it does not load. What I get is this:

Error in inDL(x, as.logical(local), as.logical(now), ...) :
   function 'cholmod_l_start' not provided by package 'Matrix'
In addition: Warning messages:
1: package 'lme4' was built under R version 2.8.1
2: package 'lattice' was built under R version 2.8.1
Error: package/namespace load failed for 'lme4'

Various trials to remove and reinstall the Matrix and lme4 packages were 
unsuccessful.

I am working on Windows XP, R-version 2.8.0:

 > sessionInfo()
R version 2.8.0 Patched (2008-10-21 r46769)
i386-pc-mingw32

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

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

Any help greatly appreciated.

R?diger Pfister

Hans-R?diger Pfister
Professor of Business Psychology
Leuphana University L?neburg
Wilschenbrucher Weg 84
D-21335 L?neburg, Germany