9-1-10,  Nice try, I thought of that and carefully reviewed my technique and also made sure I allowed extra time to elapse before I proceeded.  Still no joy after four attempts..     However,  because the update zip file was still saved in the flash drive I ran it again a few days later, to get  the exact error msg,. without having to go through that long download.   Note:  this time I  ignored  the error msg.  " try re-downloading the update pkg."  which I took to mean "save to my flash drive", for this attempt and just ran what I had already saved to my flash drive.    I don't know if that error msg would have enlightened any; however, this time there was no error msg and the download installed into the iFly without any problems.  I did the usual:  from a hot boot and selected "check for update file" just like always.   Maybe if I had tried to reinstall from the flash drive at the time of the error msg. without "re-downloading the update pkg." ??.   I  did observe that the unit got about 25% to 50% into the update each time, before the error msg. stopped it.  I  updated  the iFly  from my flash drive from a cold boot and a hot boot, didn't seem to matter still got the error msg.  Each update package I tried was fresh from the web site.  I thought at first that I was trying to update too big a file, but this successful update was six sectionals.
     Just to be clear, the problem still exists.  Just now I updated the metar/tfr file and got the same error msg.  I followed the instructions  "try "Re-downloading the update pkg" ne' save to my flash drive, per the error msg this seemed to solve it and the metar update was successful.
    The msg reads as follows:  "Unable to process update try re-downloading the update pkg.  If problem continues contact Adventure Pilot Support. Error- IOException"
      I do want to reinterate that I had no such problem with the other unit that was returned.  dp