When going to the Administration and Monitoring Console you might see this window:
In the Windows Event log on the Application Server there is a corresponding error:
ABBYY FlexiCapture Web Services: (500) Access to <your File Storage location> was denied.
Lack of permission for the Web Service to the File Storage.
Please make sure that your File Storage is shared with the account that runs the Web Services application pool. By default, it is the Network Service account.