I have installed mythTV-0.21 and its associated packages (including the mythv-backend package) on my OpenSuSE-11.1 on an old AMD Duron machine. However, when I loaded mythtv, it complained that No UPnP backends found. At this point, I am clueless and will appreciate if anyone can lend some help. 
Hallo I have the same situation Mythtv latest version and SUSE Linux 11.1 x86_64 installed and I get the message No UPnP No backends found and some other Message cannot login to database (mysql) i spend so far a lot of hours to correct the Installation reinstall mythtv and so on and withaut help this type of Error i found very often with mythtv at google search but i found no solution regards ludwig
Some months later, and I have run into the same problem. Anyone have ideas? I will post back if I find a solution.
Did you create the mysql database?
Is mysql running?
look at the mysql log file
look at the mythtv log files