only found this out today...
was shooting some pictures of the children and camera said "Memory Card Error". i have 16GB SD cards in both slots so i swapped them around and the camera worked fine. i put the "faulty" card in my laptop and everything seemed fine. so i went to Google to see whether there was any firmware updates and apparently there was. downloaded and flashed the new firmware and now both cards are fine again.
i suspect there might have been an issue with large cards in the slots since the card in Slot 1 was about half full while the Slot 2 card was empty.
the latest firmware is A:1.02 and B:1.03
hope this helps someone out there.