Importing data into Assets

Importing data into Assets

So we have a module in Zoho CRM called customers equipments. It links to customers modules, accounts (if needed) and products.
I made a sample export and created extra fields in zoho fsm assets module. The import fails.

Could not find a matching parent record for this lookup field. - Product, Customer.
or if i use id this.
Could not find a matching parent record for this lookup field. - Product, Customer.id, Account Link.id.

I am not to sure how therefor we are able to import our customers assets?