I can not import photos into lightroom 4.4 Had no problem before this time.

I can not import photos into lightroom 4.4  Had no problem before this time.  I have camera raw7.4 and use a NikonD7100.  I have a Mac using 10.6.8.  I can see the images and selected for import in Lightroom, but after I check "import" I get a message that Lightroom could not read the files.  This happens with both raw and jpeg files.  Thanks for a repl