Dear virtualArray maintainer, I'm facing the following problem. When I run "virtualArrayExpressionSets" on a few expression sets in a clean R session it works fine, but if I'm running the function again the exact same way in the same session it gives me the following error: ##Error """ Error in LastError$store(results = results, is.error = is.error, throw.error = TRUE) : Errors occurred during execution. First error message: Error in as.character.default(x): no method for coercing this S4 class to a vector """ ##Code for calling the function data.combined <- virtualArrayExpressionSets( all_expression_sets=c(eset.A,eset.B,eset.C,eset.D), identifier = "SYMBOL", collapse_fun = median, removeBatcheffect = "EB", sampleinfo = FALSE) I'm probably overlooking something obvious, so any comments are much appreciated. Thanks a lot! Best, Adrian -- output of sessionInfo(): R version 3.0.1 (2013-05-16) Platform: x86_64-apple-darwin10.8.0 (64-bit) locale: [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8 attached base packages: [1] tools splines parallel stats graphics grDevices utils datasets methods base other attached packages: [1] virtualArray_1.6.0 hugene10stv1cdf_2.13.0 hgu133plus2cdf_2.13.0 [4] affy_1.40.0 limma_3.18.3 MergeMaid_2.34.0 [7] MASS_7.3-29 genefilter_1.44.0 pvca_1.2.0 [10] MetaPCA_0.1.4 MetaDE_1.0.5 combinat_0.0-8 [13] impute_1.36.0 survival_2.37-4 MetaQC_0.1.13 [16] iterators_1.0.6 foreach_1.4.1 proto_0.3-10 [19] hugene10sttranscriptcluster.db_8.0.1 hgu133plus2.db_2.10.1 org.Hs.eg.db_2.10.1 [22] RSQLite_0.11.4 DBI_0.2-7 AnnotationDbi_1.24.0 [25] BiocParallel_0.4.1 preprocessCore_1.24.0 plyr_1.8 [28] Biobase_2.22.0 BiocGenerics_0.8.0 loaded via a namespace (and not attached): [1] affyio_1.30.0 affyPLM_1.38.0 annotate_1.40.0 BatchJobs_1.1-1135 BBmisc_1.4 BiocInstaller_1.12.0 [7] Biostrings_2.30.1 brew_1.0-6 codetools_0.2-8 digest_0.6.3 fail_1.2 gcrma_2.34.0 [13] GEOquery_2.28.0 grid_3.0.1 IRanges_1.20.5 lattice_0.20-24 lme4_1.0-5 Matrix_1.1-0 [19] minqa_1.2.1 nlme_3.1-111 outliers_0.14 quadprog_1.5-5 RCurl_1.95-4.1 reshape2_1.2.2 [25] sendmailR_1.1-2 stats4_3.0.1 stringr_0.6.2 tseries_0.10-32 vsn_3.30.0 XML_3.95-0.2 [31] xtable_1.7-1 XVector_0.2.0 zlibbioc_1.8.0 zoo_1.7-10 -- Sent via the guest posting facility at bioconductor.org.