There are maximum limits, imposed by Windows, on how long you can have an ASCI file name and the full path as follows:
MAX_FILE_NAME is 256
MAX_PATH is 260
If you come across a filename/path that is too long for Second Copy to copy, please reduce the length of the filename or the path, and see if that works.
Another suggestion: Create a sharename for the long path and use that sharename in the Second Copy profile. For example, if the source folder is:
\Documents and Settings\MyUsername\My Documents\Important Data Files\Files at Work\Accounting files\Data
Then create a sharename for the last folder Data and use the UNC path for it in the Second Copy profile. (e.g. \\servername\sharename where servername is the name of the computer and the sharename is the name of the share.)