Hello,
Sorry to hear that you are having difficulties. I know how frustrating that can be, as I used to try to list on another auction site that seemed to be "broken" and had no customer support whatsoever, and, after a couple of months, I figured my store fee was a small sacrifice to pay to run far, far away from there! Now, two years later, I happened to notice that nothing over there has improved one iota! Fortunately, I have never had a problem using Auctiva to list on ebay.
But, back to your problem....
Are you trying to do complicated HTML coding in your listings? When does the "Waiting for Auctiva to respond" message occur?
A little bit more information would perhaps help pinpoint the problem and get you a solution sooner.
I know it is a bit of the obvious, but have you cleared your computer's cache, cookies, etc.?
If someone doesn't come along and give you an answer here after awhile, I would suggest you file a Support Ticket with Auctiva.
Best of luck.