What does the error message say?
Is the transaction more than sixty days ago , or has the listing been removed by eBay?
I notice you are registered in the UK, but you are currently posting on the US Community boards on ebay.com. Have you tried leaving feedback on the UK site?
Here is an alternative link that may work better in some cases:
https://my.ebay.co.uk/ws/eBayISAPI.dll?MyEbay&CurrentPage=MyeBayFeedback&FClassic=true&ssPageName=ST...
See if the transaction appears there, and then try the "Leave Feedback" link in the item row.
