We have had many problems reported from AOL users. Disable all their "stuff" that you can. It's just not worth what it does to your computer.
Whenever you see a "CRC" error, it means Cyclic Redundance Check, which is the error checking embedded in a downloaded file, and then computed on it also. Whenever a CDR error happens, the file contents are bad. As Dale said, the .gif image that was reported bad doesn't affect the program functioning, but as you said, redownloading fixed other problems.
Always redownload when a CRC error is reported. It was a bad transmission that damaged data. Anything goes at that point.
