First, let me apologize for my conspicuous absence from this thread. I believe I had good reason - read on:
My Auctiva issue with extreme slowness is resolved! By sheer coincidence, my wife bought a new laptop with a wireless LAN card in it (the day before my original post). This required me to get a new router with wireless capabilities. The instant I replaced the router, my Auctiva issue completely went away. (For clarification, I am still using the same computer, her new laptop just prompted me to buy a new router.) The initial login page (and these forums) loaded quickly as always, but all of my issues with creating, saving and viewing listings immediately went away. No more 'jumping', pages load/refresh in maybe 5-10 seconds instead of the old 40 seconds to a minute! I can also clearly see the difference visually with my DUMeter app that monitors and displays the upload/download speeds. No more back and forth, back and forth 'handshake' at 30-40 kB/sec like it used to do, now it is just my outgoing request, and then a speedy download of a new page from Auctiva at 150 - 200 or more kB/sec.
Here is what has NOT CHANGED:
1) My ping times to the auctiva server are still generally the same, as they are with all other sites (I have always assumed, and correctly so I think, that this is not an Auctiva bandwidth issue, or everyone would be having trouble)
2) All other sites, which I never had any trouble with, still load and behave exactly as they always did
3) My upload/download speeds, as measured at http://www.speakeasy.net/speedtest/ are unchanged with the new router
When I stated in my initial post that I had eliminated the router from the system and there was no change, I did eliminate the Netgear router that was at my computer, but probably NOT the LynkSys at the incoming port. (This part of my troubleshooting was done many months ago, so I don't remember it all that well.)
What I do know is that removing the Cisco LinkSys Cable/DSL router and replacing it with a Netgear router fixed my issue. The other Netgear router is still in the system and my computer that is used for Auctiva is still hardwired to the line, not wireless.
The reason I have not posted any further in the thread until now is that I wanted to thoroughly test this and make sure that it was not a fluke. I did go back to the LynkSys and instantly had the same issues. I have been using the Netgear now all of this week, every night on Auctiva and it has run super smooth every time. No more getting up to do an errand, checking e-mail, getting a snack, etc. waiting on Auctiva pages to refresh!!
So it is up to someone smarter than me to explain why a LinkSys router would cause so many issues with ONE, and ONLY ONE website. My hope is that everyone who reads this and is having trouble with Auctiva slowness looks up from their screen right now and sees a LynkSys router - if so, SWITCH IT OUT!