Solution : https://service.sap.com/sap/support/notes/520227 (SAP Service marketplace login required)
Key words : 
delta download fails, attached correction instructions, error message com_product502, terms com_product502, program error, /3 backend system, crm server, sales taxes, change data, set crmm_pr_tax
Related Notes : 
       
| 872533 | FAQ: Middleware |