I was also having a problem with the .ics file with korganizer.
korganizer does not seem capable of handling the TZID:EDT and wants to
interpret every date/time at UTC. By swapping the timezone in
korganizer to UTC and then back choosing "keep times" / "move times"
where appropriate I was able to build a export a .ics file without the
TZID:EDT .
Please try the following file:
http://mysite.verizon.net/vzeq1z17/temp/DebConfAdjusted.ics
Also, after importing, please verify the times are correct for your
situation against the DebConf10 website..
-David