Sometimes the Statistics Collector stops creating new entries in the Statistics Report Database, although all tasks are up and running, and you have to delete the statrep.nsf DB in order to get the server to create a new one and start logging again. The problem is that you will have to do this process again sometime in the future. There is another way to get the stats back and it needs to be done only once:
without recreating the DB:
1. On the workspace, click with the right button on the Statistics Report icon;
2. Select Database, Properties;
3. Click on the Advanced tab;
4. Mark the "Allow more fields in the database";
5. You are done and your statistics will never stop logging again!