Diagnosis
No active delta initialization available for this DataSource.

Procedure
You have to initialize the delta load for a DataSource before you areable to load the delta data from it.
If you want to load deltas only for the purposes of testing, or you donot require any initialization data (because you have already uploadedit using a full upload, for example) use an initialization simulation.
This way, only the init. entries you require are made in the controltables of the source system, and a 'dummy' entry appears in theMonitor, setting the load status to green.
No data is in fact loaded, however, and the initialization takes only afew seconds to complete.