Weird. Sounds like an ACR issue, but if you're using Lightroom then you should already be pretty up to date. Are you transferring the photos onto your hard drive before you try to import them into Lightroom, or are you trying to import them directly from the camera?
Regardless, I'd update your ACR just in case that's the issue...
http://www.adobe.com/products/photoshop/cameraraw.html