I'm sorry to hear about the difficulties you are experiencing. I am not aware of any inherent compatibility issues between the Auctiva Uploader and the latest Java release (Version 7 Update 55), so I believe we will be able to help you through this issue by doing some Java related troubleshooting.
Although I cannot be certain exactly what went wrong with the update to cause this issue, the first thing I recommend trying which may help is clearing your browser cache and then restarting your browser, which can be done via the following process through Internet Explorer 11.0:Select "Internet Options" from the "Tools" menu (has an icon that looks like a gear and it in the upper right corner) within Internet Explorer. Then, under the "General" tab, click the "Delete" button in the "Browsing History" section.
On the ensuing pop up window, make sure "Temporary Internet Files" and "Cookies" are selected and click the "Delete" button below.
Once this process has been completed, close and re-open your Internet Explorer web browser for the changes to take effect. Also, please ensure that only one browser window is open when you are doing this or your cache may not empty properly.
If you continue to encounter the same behavior after doing so, I then recommend completely uninstalling any versions of Java you currently have installed using the “Remove a Program” option in your Windows Control Panel, and then reinstalling the latest version of Java anew from: http://www.java.com/en/
Hopefully one of these things will do the trick. If you are still unable to use the Auctiva Uploader after trying these options, please contact our Customer Support team directly from under the “Help” tab on our site and we will be happy to continue working with you on this.