If you are brave enough to be using the early adopter releases of ODMr you may have run into the issue with your workflows not running.
When you go to run your workflow you will get the following window and nothing else happens.
To get passed this you will need to kill SQL Developer using the task manager or equivalent.
So how do you stop this from happening so that you can get your workflows to run. The simple solutions is that you need to have the workflow tab open for the workflow to run correctly.
To do this you need to make Oracle Data Miner visible, by selecting Tools from the menu, then Data Miner and finally Make Visible
Then you will need to go to the View menu option, then select Data Miner and then Workflow Jobs
Now your workflows will work and complete.
Hopefully this will be fixed in the production release of ODMr 4 (SQL Developer 4)