Yes, it's significant... it means the email address which received your payment is not linked to a PayPal account. Possible reasons for a payment being sent to an unregistered email address are... the seller may have misspelled his PayPal email address in the payments section of the eBay listing, or he may have entered an old email address, or he may need to confirm his email address.
The seller needs to correct this from his end... here's some of the steps he needs to take...
To check which PayPal email address was used in the eBay listing, the seller needs to click on the "Sell similar" link for that eBay listing and look in the payments section for the PayPal email address.
If the seller has access to that email address, he should login to his PayPal account and "Add" the email address to his account. The payment will show up right after he confirms the email address.
If the email address is already added to the seller's PayPal account but is unconfirmed, the seller needs to click on the "Confirm" button to initiate the email confirmation process.
If the seller is unable to add and confirm the email address, you will need to cancel your payment, and the seller will need to send you an invoice (using the "Request Money" tab - "Create an Invoice" option) from his PayPal account using a confirmed email address... this will enable you to pay to his correct PayPal email address.