Ppscan runs a state-based scan for punctuation on a text file that has been prepared for submission to Project Gutenberg. It is checking the curly quotes, so the file should be UTF-8 with curly quotes. The user uploads a text file, chooses any options to override deafults and clicks Submit. After the prgoram has analzyed the file, it presents a link to the results for the user to download or view. In that file, search for the "@" symbol, which marks where the program thinks there might be a problem. Usually you can spot a problem or a false positive quickly. If you need to know more about what the program questioned, there is a list of errors, including the description, at the end of the results file.
Some users prefer a more complete error message at the point where the error was detected. If the user chooses the "extended report format" instead of a single "@" they will get an error like [@CODQ] saying not only that there is a suspected error but that it is a "consecutive open double quote" error. The complete list is printed at the end of the report file for reference.