Hi, Using R 2.0.0-pre, gcrma 1.1.0, win2k: > library(gcrma) > atom.gcrma<-gcrma(atom.batch, type="fullmodel", fast=FALSE) Computing affinities.Done. Adjusting for optical effect.............Done. Adjusting for non-specific binding.Error in bg.adjust.fullmodel(pms[, i], mms[, i], pm.affinities, mm.affinities, : couldn't find function "gcrma.bg.transformation" This is similar to the problem reported at: https://stat.ethz.ch/pipermail/bioconductor/2004-April/004394.html Thanks, Jeff. __________________________________ Jeffrey Rasmussen Research Consultant, Bioinformatics Department of Immunology University of Washington