Hi Halee77,
I have not been able to locate the account in question to verify this, but it sounds like your sister's relist attempts most likely failed because the closed listings she attempted to relist were not available on eBay any longer. Ebay usually only keeps closed listing data available on their site for about 60 days after the items have ended.
In order to verify this, your sister would just need to click the item number links next to a couple of these items from her Closed Listings page within Auctiva. If those links take her to eBay pages that indicate the requested item is no longer available, that would mean the listings have been deleted from eBay's database and that they can no longer be relisted as a result.
If the closed listings in question were originally posted to a different eBay account than is currently linked to her Auctiva account, it would also be expected for API errors to be returned if she were to try and relist those items from the Closed Listings page.
If the items in question were originally posted through Auctiva, your sister may still have the listing details stored on the Saved Listings page within her account. If so, she should be able to post them from there. Otherwise, the listings would need to be recreated and posted as new listings.
Only eBay listings should show up on the Closed Listings page within Auctiva to begin with so I don't believe the fact she had attempted to sell those items on eCrater would have anything to do with this situation.
If it sounds like I have not understood the situation accurately, or if you have any other questions, please feel free to contact our customer support team by mousing over the "Help" tab and selecting the "File Support Case" option.
-Mike