A CRC error means the floppy controler has calculated a checksum for the data read and found it does not match the checksum recorded when the sector was written. Pretty much always badly written data or bad media.

I have recovered some files using Gibson's SpinRite (yes it can do floppys too, though very slowly), but there is likely to be some damage. Any damage is fatal to a spreadsheet file, but many word processor documents can be largely recovered.