I get the error message “Item 123456789 from eBay Motors was skipped because it was not listed on eBay US”

According to the eBay API, eBay Motors and eBay US are two different sites – but by default, the importer will only import products which were listed on the eBay site defined in WP-Lister » Settings. 

To import items from all sites, please visit WP-Lister » Import » Advanced Settings and set the Import from all sites option to Yes.