It happen to me as well.
Park car in the LUG for 2 weeks for oversea trip
then first day back to work put the car in the office car park with 40 + degree temp.
around 6PM, when i start the car and trun on music........... the bosh unit make some noise ..5 sec later "CD ERROR FO" showed on the screen
so i guess it could be the "heat" issue.....