I've found an easier way to check an md5 sum, or any other checksum for that matter. Just use this command:
If there is an error, it will show the file name and the real checksum of the file. If there aren't any errors, then nothing will show up. You can do this for mutliple files by putting a semicolon (;) between the above code for each file.
md5 file_to_check | grep checksum_of_file