CRC (cyclic redundancy check) errors mean the file is corrupt. If you get a CRC error from files on a CD/DVD, you can check the disc for scratches, clean the lens, reburn at a slower speed, or try a new data cable. But files that have been downloaded and give this error usually need to be downloaded again, unfortunately.
If you're using FlashGet, or any other download manager, it's generally safer to set the "Threads from main site" option to 1. Higher numbers can cause problems, even though they give faster download speeds. Also, some sites don't support download managers properly and don't allow partially downloaded files to be paused and resumed.
I don't know if this will work, but it's worth a try...... Burn the files to DVD at x1 or x2 speed, then run
CDCheck. It will test the files to see if they are corrupt. Then, if it finds any errors, it will try to recover and fix them. You can then burn the fixed files to DVD or run from your hard drive.