Can't save files to WD Passport

Help required please. I bought a WD passport yesterday and successfully installed, formated and saved files to the drive. I hibernated my PC for the evening, started up PC today and now there are no files on the drive. There was a message saying something about E:MFT, but I do not know what this meant.

 I can see the WD Passpot HD, unlock it, but when I now try to save any type of file I receive a message which says that the drive is read only. I have shut down my pc and restarted the thing, but it this has not made any difference.

I was goingto uninstall and reinstall, but I have noticed that the some of the main foldere that were there when I initially installed are no longer there… HELP

Ouch, this is not good, try to check your disk for errors, using Windows checkdisk: