OK, you were probably bitten by https://github.com/dreamwidth/dw-free/issues/2318. I'm afraid the notifications you never received are well and truly lost. There still is a solution for you that will let you use notifications in the future, and that is to point @THESCHWARTZ_DBS to where the tables actually live. Specifically:

1- Open ext/local/etc/config-private.pl (not etc/config-private.pl) with your favorite editor
2- In %DBINFO, note what user and pass are set to
3- In @THESCHWARTZ_DBS, make sure that user and pass match those in %DBINFO
4- Still in @THESCHWARTZ_DBS, change 'dw_schwartz' in dsn to 'dw'
5- Still in @THESCHWARTZ_DBS, add the following line before the closing }:

prefix => 'sch_',

6- Check @THESCHWARTZ_DBS: it should now look something like:

    @THESCHWARTZ_DBS = (
            {
                dsn => 'dbi:mysql:dw;host=localhost',
                user => 'yourusernamegoeshere',
                pass => 'yourpasswordgoeshere',
                prefix => 'sch_'
            },
        );

(perhaps with different indentation)
7- Save your changes
8- Test as much of the features that rely on TheSchwartz that you can and care for (for a should-be-complete list, see TheSchwartz workers in http://wiki.dreamwidth.net/wiki/index.php/Workers#List_of_workers )