I am trying to do the Heteroplasmy tutorial from the tutorial page so that I can use it as an exersize for an introductory bioinformatics class I am teaching. Everything seems to work fine except for the filter pileup tool. After I generate the pileup of mapped reads I go to Filter pileup to filter out positions with low coverage the "select dataset" field says that there are no pileup datasets available even though I just made a pileup file. Additionally, when I view the pileup file there are only 5 column when there should be 6. It looks like the "read bases" (column 5) is missing. Is this a known problem? I was planning to use this tutorial on Monday so any help would be greatly appreciated! Thanks in advance.