Zabbix now seems to require MySQL 4.x, so in order to roll the RPMs for EL3 (stock is MySQL 3.x) I had to recompile upstream EL4 MySQL and the corresponding EL3 dependencies. To make a long story short, if you intend to run the Zabbix server on an EL3 box you will need to install my contributed dependencies or roll your own. See this thread for downloads:
Enjoy,
/Christian
Enjoy,
/Christian