I seem to be having an issue with Ucsctrack in GViz: exfail=UcscTrack(track="CpG Islands", chromosome="chr6", genome="hg19", start="chromStart", end="chromEnd", name="CpG Islands", from=31731740, to=31736112) Error in function (classes, fdef, mtable) : unable to find an inherited method for function ".buildRange", for signature "NULL", "logical", "logical", "NULL" This occurs when I try to get an area where there are no annotations(i.e. expected behavior is an empty object). Is this a known bug? I'm using the release version. Traceback and sessionInfo included below: Thanks, Winston Timp -- Winston Timp (410)-417-8467 Postdoctoral Fellow Johns Hopkins Medicine [[alternative HTML version deleted]]