Xacti VPC-HD1000 "Problem with SD card" "FORMAT / FULL FORMAT"

I have a problem:

I just bought a Xacti 1000 and a 16GoB SD(HC) card (Class 6, from Apacer).
When I first powered my cam with the card in it, and selector on CAM, I read the message "Format / FULL FORMAT", and the cam said ("problem with the SD card", with a woman's voice...!).

I tried a few things:
- tried to re format the card with the cam: the process stopped 2h30 latter with the batt low level... (2 times),
- put the card in a computer: but it was not even detected;
- tried another PC wich could see the card and formated it in a 1 partition FAT32 format (as specified in the manual),

Nothing worked! then I tried another card (1Gb Scandisk SD card):
-same screen on Xacti: "FORMAT / FULL FORMAT"
-formating with Xacti didn t succed either....

Given that I saw this cam working (the seller demontrated the cam right when I bought it!), I assume it should work and I am doing something wrong, or I should do something that I DON'T know!!!

HELP!

;)