I am following the vignette provided by the 1.2.2 rtracklayer package -- and delighted to find such capabilities in bioc! When I call, browseGenome(subTargetTrack) I get this error (with traceback and sessionInfo to follow). Can anyone help? - Paul Error in as.numeric(hgsid) : cannot coerce type 'externalptr' to vector of type 'double' > traceback () 5: browserView(<s4 object="" of="" class="" "ucscsession"="">, <s4 object="" of="" class="" "genomesegment"="">) 4: browserView(<s4 object="" of="" class="" "ucscsession"="">, <s4 object="" of="" class="" "genomesegment"="">) 3: do.call("browserView", viewParams) 2: browseGenome(subTargetTrack) 1: browseGenome(subTargetTrack) > sessionInfo () R version 2.8.1 (2008-12-22) i386-apple-darwin8.11.1 locale: en_US.US-ASCII/en_US.US-ASCII/C/C/en_US.US-ASCII/en_US.US-ASCII attached base packages: [1] splines tools stats graphics grDevices utils datasets methods base other attached packages: [1] rtracklayer_1.2.2 RCurl_0.94-0 org.Hs.eg.db_2.2.6 microRNA_1.0.0 Rlibstree_0.3-1 matchprobes_1.14.1 affy_1.20.2 [8] limma_2.16.4 genefilter_1.22.0 survival_2.34-1 humanStemCell_0.2.0 hgu133plus2.db_2.2.5 RSQLite_0.6-9 DBI_0.2-4 [15] AnnotationDbi_1.4.2 Biobase_2.2.1 loaded via a namespace (and not attached): [1] Biostrings_2.10.15 IRanges_1.0.9 Matrix_0.999375-18 XML_1.95-2 affyio_1.8.0 annotate_1.20.1 grid_2.8.1 [8] lattice_0.17-17 preprocessCore_1.4.0 rJava_0.5-1