Hi Nannysue,
I previously overlooked the fact that you pasted your description HTML onto the PracticeBoard. The line of code that eBay is rejecting your listings based on is actually the Paypal pop-up Javascript, which is as follows: onclick="javascript:window.open
As "meow" mentioned, if you replace the Paypal pop-up window code with a simple link to Paypal, you should be able to post your listings without making any further changes. The Sellathon counter Javascript is actually in compliance with eBay policy.
-Mike