Hi cripsy,
Thanks for contributing to our forum. If you receive a message indicating that your listing did not pass validation and needs to be edited when attempting to post an item through Auctiva, it almost definitely means that at least one required field on the lister page was not filled in.
If you open up the item in question on your Saved Listings page and press the "Error Check" button at the bottom of the page, you should receive a message explaining exactly why the listing did not pass validation.
If you need any further assistance with this situation, please feel free to contact our customer support team by mousing over the "Help" tab and selecting the "File Support Case" option.
-Mike