Hi David,
I have SUDO rights, no doubt, sudo su works, and I use it every day for backup, upgrade,etc. and I'm the only user of this computer. But the password is not accepted by the installer.
I read another post where you suggest to launch the installer with SUDO. The installation works, but then the software does not work well, no map, no acces to grib files, I don't know exactly ..
Thanks.