Problems with Excel Importer: first row is not processed correct

I use the Excel Importer vs 8.2.2 in Studio Pro 8.15.2. I try to import Excel files from an Access database: each sheet has the information from one entity; it contains the attributes and the foreign keys. I have configured my Excel file with in each row (in this sequence) the primkey, its attributes and lastly, one or more foreign key references to other entitities by providing the id's. It works fine except for the first row: it accepts the first foreign key reference but skips the other references on the first row. Starting at the second row everything seems ok. Any ideas what causes this problem and how to solve it?   
1 answers

Do you have a header row specified?