Were the complaints in reference to Y! Fantasy not working on the Kindle Fire, or other websites not working on Kindle Fire? I don't own a Kindle Fire, but I do know Yahoo does an excellent job maintaining compatability between all the different browsers and devices.
What is the security warning that you get? What kind of help did you find when you searched the error message?
Just fantasy baseball not working. I haven't really tried other yahoo sites with it.. Sorry, I don't know what the security warning I got and I haven't received any help. The main issue is the page freezes when I try to make lineup changes.