Thanks for the win32 build of genefilter for Rv2.0. Have run into an error when using genefilter to run a t-test. Error seems to indicate genefilter is nor recognizing format of eset. Please advise. Thanks again. > data AffyBatch object size of arrays=1164x1164 features (42346 kb) cdf=HG-U133_Plus_2 (54675 affyids) number of samples=4 number of genes=54675 annotation=hgu133plus2 > eset<-rma(data) Attaching package 'hgu133plus2cdf': The following object(s) are masked from package:hgu133a2cdf : i2xy xy2i Background correcting Normalizing Calculating Expression > eset Expression Set (exprSet) with 54675 genes 4 samples phenoData object with 2 variables and 4 cases varLabels Covar1: mutant Covar2: wt > tf1<-ttest(eset$mutant, p=.001) > ff2<-filterfun(tf1) > wh2<-genefilter(exprs(eset), ff2) Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : invalid variable type In addition: Warning message: is.na() applied to non-(list or vector) in: is.na(m) >