ADE 3.0

I cannot download books from the local library. I keep getting asked to download ADE 3.0 even though it has been installed on my computer. I uninstalled it and reinstalled it again but every time I try to download the book it keeps asking me to install ADE 3.0.  I have been downloading books on my Kobo for the last 5 years without any problem. I appreciate all the help I can get.