Your web connector is running too fast. The web connector is attempting to sync the previous task and the next task is trying to queue.
Here are the steps:
In your windows taskbar, right click and select Task Manager.
Stop the web connector process. If you use Windows 7, then right click QBWebConnector and click end process.
End the QuickBooks process by searching for QB32.EXE and click end process.
Restart QuickBooks and the web connector.
Set the web connector interval to 60 minutes.