Hi,
1. Please check BOM field components
2. Defined or not in the child quantity also
3. It could be like done have defined any child item under BOM or it does not have any quantity under it
4. As production order need BOM to be defined in, it should be legitimate
There are many different types of error messages received while using SAP Suites which include different types of errors received while performing different operations against any SAP products like CRM, ERP.
Below link it may help you,
SAP Internal Error: 3702
Production table details & type :
Production Order Overview - SAP Help Portal
http://help.sap.com/saphelp_sbo882/helpdata/en/68/9975f9caea438ba98206fce1573bcb/content.htm
Sap Error code details :
http://www.sqlserverf1.com/tag/sap-internal-error-3702/
Thanks & Regards,