I have been setting up a new install of zm on OpenSuse 13.1, which has mariadb as the default replacement for mysql. The installation appears to default to using strict mode, which then causes zm problems in more than one area but the place I found it was trying yo add a monitor, when it gave an SQL-ERR complaining that there was in incorrect decimal value for MaxFPS.
If you get rid of strict mode then zm works OK.
The change I made was to comment out the line sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES in /etc/my.cnf