Hi Jam Handy (& adriana),
I'm sorry to hear about the difficulties you are encountering. The “Install Plugin” link in the message you referred to *should* install the Java plugin that is required to use the Auctiva Uploader through Firefox or Chrome and I am not certain exactly why you have been unable to install it successfully.
However, as has been discussed over the course of this thread, several recent updates of Java (including the latest one) have been flagged for containing vulnerabilities and it seems likely that this issue is related to the handling of one of these Java warnings.
For the time being, you could potentially continue using the Auctiva Uploader without enabling Java by switching over to the Internet Explorer browser.
I don't feel I have enough information about each of your situations to make any specific recommendations, but please feel free to contact our Customer Support team by mousing over the “Help” tab and selecting the “File Support Case” option if you need any further assistance.