LR says my files are damaged, PS says can't recognise file type.

Hi. I'm freaking out because this is what's happening:

1. Downloaded all my files (combo of CR2 and jpg) on to HD.
2. Import in LR
3. Only jpg and some CR2 has viewable thumbnails
4. Imported the jpgs but all CR2 came up with this msg: 'The file was not imported. The files appears to be unsupported or damaged.'
5. Can't open these files either with PS. It says it doesn't recognise this file type?
6. BUT it opens in PREVIEW and I had to resave it to psd. This seem to work cos NOW PS can open it.

Can anyone explain what's going on??
Thanks in advance.
Jules

I have found that LR goes a bit stupid when it is used in a session too long. I have gotten the exact message that you did and exited and re-started Lightroom and all was well. It seems a bit better in 2.x but certainly under 1.4.x I got it if I had worked in Lightroom for several hours without starting a fresh session every now and then.