[BioC] rtracklayer bug? cannot coerce type 'externalptr' to vector of type 'double' in browseGenome call

[Paul Shannon]

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