Hi When I try to load matac it says library(macat) Loading MicroArray Chromosomal Aberration Tools... Loading required packages... You need package 'stjudem', if you want to see the demo and examples. Type 'loaddatapkg("stjudem")' for automatic install! Type 'demo(macatdemo)' for a quick tour... Error in if (.Platform$OS.type == "windows" && require(Biobase) && interactive() && : missing value where TRUE/FALSE needed Error in library(macat) : .First.lib failed for 'macat' I am using R 2.0.0 Furthermore. Where do I get a windows version of stjudem. I have not found one anywhere Cheers Michael