Thank you for contacting us.
In cases when you can not see the error description you can contact us so that we will provide you all details. In this run you have got issues listed below:
1. Field integrity exception: Quantity (quantity must be nonzero).
This error says that Salesforce does not allow specific fields (i.e. opportunity line items value) to have a value of 0, please change the quantity to a non-zero number.
You can also contact Salesforce support and refer to this link https://developer.salesforce.com/forums/?id=9062I000000Qw0wQAC
2. Foreign key external ID: ******* not found for field Netsuite_Sales_Order_ID__c in entity Opportunity
Although the Netsuite_Sales_Order_ID__c column is mapped to an ExternalId column, it looks like there is no match between Netsuite_Sales_Order_ID__c and OpportunityID columns.
It is necessary that the Source Column (Netsuite_Sales_Order_ID__c) match the External ID Column in order to find and insert an OpportunityID value for the following mapping (see attached screen).
3. No record found for the specified lookup condition.
To use the Lookup mapping, you need to have a column (or a set of columns) that uniquely identifies a record, other than the primary key or Lookup Column.
Please try to select another field in Lookup Key column.If error returns please check whether the proper record for lookup condition exists.
Could you please check and let us know the result.