[BioC] Limma & Imagene

[cv.vc]

I use Imagene 4.0 and Limma R package.
My source file are into R directory ... and this is my R shell:

> library(limma)
>
YourSample<-read.table("TargetsSampleTarget.txt",header=TRUE,sep="\t",as.is=
TRUE)
> YourSample
  SlideNumber FileNameCy3 FileNameCy5     Cy3       Cy5
1           1       1.txt       2.txt treated untreated
2           2       3.txt       4.txt treated untreated
3           3       5.txt       6.txt treated untreated
> RG<-read.maimages(slides, source="imagene")
Error in match.arg(source, c("spot", "spot.close.open", "genepix",
"quantarray")) :
        ARG should be one of spot, spot.close.open, genepix, quantarray

What is the problem? Thanks