The error messages 'The specified @name already exists' for the Datamart Extraction job is caused by SPIDS still processing a previous execution of the job.
See also Knowledge Document:kb000049533
In the specific case here, the error may also show up when having set up the following environment:
- MSSQLServer with two CA PPM schemas, installed on a single server, for example for CA PPM Production and Development.
- Starting the Datamart Extraction Job at the same time for both CA PPM environments.