I've had a similiar problem pop up with ADATA Class 10 16Gb device in my DMC-ZS3.
The card worked fine for the longest time, then after writing a video it came up with a memory card error.
Put it in a PC Card reader just fine.
Formatted it in the PC with different SD formatters and the camera still won't recognize it.
The weird thing is a 2nd 16GB Class 10 (bought at the same time, same brand) which had formatted and worked fine when inserted has the same "Card error" message.
Both cards seem fine in the PC and now neither works in the camera when both previously did.
Weird or expected for Class 10 early cards?