A “CRC error” is encountered when the data from the floppy disk is not the same when it was written originally. Every time you copy files to a device like this it also stores some numbers and when you perform copy operations the hardware and the operating system check for those numbers to match, which in your case do not. Another problem is that you have a bad disk and needs to be replaced or just formatted and then you could try and copy the original data again. A recovery software would do no good because it cannot modify the structure of the CRC number.