File couldn't be opened

I put the sdxc card in the computer, I transfer the video from my disc to my external drive: The folders includes: a private folder and a DCIM folder (video is avchd). When I go to final cut x, I go to import file which sees the avchd files. It imports the video into final cut x. I see the video and it lets me put it into the time line however when I try and place video into a bin I get the error message the file.....couldn't be opened because there is no such file. I tried to changed the format of the files from avchd to .mov by using a file convertor software. When files were converted to .mov I did the same import process by going to import in final cut x. The same process as above and the same error message.