Second Copy can crash with a fatal error message due to a corrupt log.rtf file. Remove this file and run scandisk.
Second Copy 7 stores its log entries in a file called log.rtf under "\Documents and Settings\<Username>\Local Settings\Application Data\Centered Systems\Second Copy" folder. (where, <Username> is the currently logged in username.)
In Vista, log.rtf file is stored under "\Users\<Username>\AppData\Local\Centered Systems\Second Copy" folder.
Second Copy 2000 stores its log.rtf file under "\Program Files\SecCopy" folder.
Here is an article from Microsoft Online Support site explaning fatal errors: