Hi All: I am trying to analyze C. elegans tiling array data using the AffyTiling library. I use the bpmap file provided by Affymetrix. The program reads CEL & bpmap files but exits with error message after traformation (see out put below). Can anybody explain how I should avoid this problem? Any help would be appreciated. Feseha > library(AffyTiling) > library(preprocessCore) > EXP <- AnalyzeTilingCelFiles(dir(pattern=".cel|.CEL"), > "Ce25b_MR_v02-2_ce4.bpmap") [1] "Importing BPMAP file." [1] "Reading CEL Files & Extracting Intensities." [1] "Quantile normalizing/ log(2) transform." [1] "Finalizing data." Error in dimnames(x) <- dn : length of 'dimnames' [2] not equal to array extent