unable to create num sequence for workflow in AX 2012 FP?

Hi, when i try to create a number sequence for workflow or Instance ID, i am getting the following error - I set the scope to shared and added a segment with alpha '######'     

start 1; 999999; next: 2

When I try to add reference -: workflow  & workflow ID, following error is reported:  

Cannot create a record in Number sequence references (NumberSequenceReference). Datatype number sequence properties: 4873.The record already exists.

Any idea how to resolve this?  We are not able to add any workflow!

many thanks