Sorry but you're having other issues.
As much as the DVC member site sucks (and it
does in the sense that it is, for the most part, worthless), it does work and very reliably from my experiences. I login EVERY day and I can't remember the last time I had any issues with the site
working.
Many sites these days are only certified to be compatiable with 1 or 2 major browsers. I know Disney certifies on IE and while I don't have time to go through the available source, I can see some stuff on there that
could be IE proprietary.
If you're using Windows, you likely should be using IE as your primary browser. It is available for download on other platforms as well.
Could you please post the complete text from the browser window that is the error you are receiving? It would certainly help me in diagnosing your issue further.