Lightroom :: 4.3 Doesn't Import JPG?

I have recently upgraded to a new computer with windows 8 preinstalled. When i tried to import jpg with lightroom today i discovered this problem; The thumbnails shows as usual, but when I click the import button, it runs through the files and tells me that non where imported because the file could not be read. I have tried both with a card reader, and directly from the camera. No luck. I works fine when I try to copy in windows explorer.