Okay. Small update.
I got it all working!
For some reason the password that I got the 1st time from "/usr/local/ispconfig/interface/lib/config.inc.php" did not match at all in what I used in "/config/db.inc.php"
I'm 100% sure that I did put in the correct password, but again it did not match at all when I had a new look today!
I did do an apt-get update and apt-get upgrade today, but this could not have caused this problem!
Anyway. RoundCube (and the extra two options) are now working great!