[R] Problems with expresso

[Markus Schmidberger]

Hello,

I want to use expresso for preprocessing the hgu133a-spikein data from 
affycompII. But there is an error:

 > library(affy)
 > path <- "z:/Microarray/hgu133a-spikein/rawdata"
 > celFile <- list.celfiles(path=path,full.names=TRUE);
 > affyBatch <- ReadAffy(filenames=celFile[1:6]);
 > eset1 <- 
expresso(affyBatch,bgcorrect.method="rma",normalize.method="quantiles",summary.method="medianpolish")

background correction: rma
normalization: quantiles
PM/MM correction :
expression values: medianpolish
background correcting...done.
normalizing...done.
Fehler in function (classes, fdef, mtable)  :
        unable to find an inherited method for function 
"computeExprSet", for signature "AffyBatch", "NULL", "character"

sessionInfo()
R version 2.5.1 (2007-06-27)
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] "tools"     "stats"     "graphics"  "grDevices" "utils"     
"datasets"  "methods"   "base"    

other attached packages:
hgu133atagcdf          affy        affyio       Biobase
     "1.16.0"      "1.14.2"       "1.4.1"      "1.14.1"

Whats wrong? The function "computeExprSet" exists in library(affy)

Thanks
Markus

-- 
Dipl.-Tech. Math. Markus Schmidberger

Ludwig-Maximilians-Universität München
IBE - Institut für medizinische Informationsverarbeitung,
Biometrie und Epidemiologie
Marchioninistr. 15, D-81377 Muenchen
URL: http://ibe.web.med.uni-muenchen.de 
Mail: Markus.Schmidberger [at] ibe.med.uni-muenchen.de