SAP Note 22747 - Setting up the client for Workflows

Symptom:

Workflow cannot be started. Message WL404 displayed when a workflow is started directly in transaction SWUS. This only occurs in the FCS release, not in release 3.0A or later.

Cause and prerequisites

The client has not yet been setup for workflows.

Solution
Before using workflows in a new client you must configure the number range for object SWW_WIID. Failure to do this will result in error message WL404 being displayed whenever an attempt is made to start a workflow.
To configure the number range start transaction SWUW. Inspect the number range to see if interval '01' has already been created. If it has not, create the interval '01' with the maximum range possible. Do not check the external-flag checkbox.
After you have saved the changes you should check that the workflows you intend to use have been activated and that the event-coupling is active too.